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Proposed Framework for Evaluating the Safety of
Dietary Supplements -- For Comment
Committee on the Framework for Evaluating the Safety
of Dietary Supplements, National Research Council
ISBN: 0-309-58358-6, 156 pages, web only, (2002)
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Proposed Framework for Evaluating the Safety of Dietary Supplements -- For Comment
i
FOR COMMENT
Proposed Framework for Evaluating the Safety of Dietary Supplements
Committee on the Framework for Evaluating the Safety of Dietary Supplements
Food and Nutrition Board
Board on Life Sciences
INSTITUTE OF MEDICINE
NATIONAL RESEARCH COUNCIL
NATIONAL ACADEMY PRESS
Washington, D.C.
Copyright © National Academy of Sciences. All rights reserved.
ii
NATIONAL ACADEMY PRESS 2101 Constitution Avenue, N.W. Washington, DC 20418
NOTICE: The project that is the subject of this report was approved by the Governing Board of the National Research Council, whose members are drawn from the councils of the National Academy of Sciences, the National Academy of Engineering, and the Institute of Medicine.
The members of the committee responsible for the report were chosen for their special competences and with regard for appropriate balance.
Support for this project was provided by Food and Drug Administration under contract number 223-00-2458. The views presented in this
report are those of the Institute of Medicine Committee on the Framework for Evaluating the Safety of Dietary Supplements and are not necessarily those of the funding agencies.
This report is available for downloading as a pdf file at www.nap.edu and at www.iom.edu/fnb.
For more information about the Institute of Medicine, visit the IOM home page at: www.iom.edu.
Copyright 2002 by the National Academy of Sciences. All rights reserved.
Printed in the United States of America.
The serpent has been a symbol of long life, healing, and knowledge among almost all cultures and religions since the beginning of recorded
history. The serpent adopted as a logotype by the Institute of Medicine is a relief carving from ancient Greece, now held by the Staatliche
Museen in Berlin.
iii
Knowing is not enough; we must apply.
Willing is not enough; we must do.
—Goethe
INSTITUTE OF MEDICINE
Shaping the Future for Health
iv
The National Academy of Sciences is a private, nonprofit, self-perpetuating society of distinguished
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Dr. Bruce M.Alberts is president of the National Academy of Sciences.
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The National Research Council was organized by the National Academy of Sciences in 1916 to associate
the broad community of science and technology with the Academy's purposes of furthering knowledge and
advising the federal government. Functioning in accordance with general policies determined by the Academy,
the Council has become the principal operating agency of both the National Academy of Sciences and the
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Dr. Bruce M.Alberts and Dr. Wm. A.Wulf are chairman and vice chairman, respectively, of the National
Research Council.
www.national-academies.org
v
COMMITTEE ON THE FRAMEWORK FOR EVALUATING THE SAFETY OF
DIETARY SUPPLEMENTS
BARBARA O.= SCHNEEMAN (Chair), Departments of Nutrition and Food Science, Division of Clinical
Nutrition and Metabolism, and Office of University Outreach, University of California, Davis
DANIEL L.= AZARNOFF, D.L.= Azarnoff Associates and Clinical/Regulatory Affairs, Cellegy Pharmaceuticals,
South San Francisco, California
CINDY LYNN CHRISTIANSEN, Center for Health Quality, Outcomes, and Economic Research, Bedford
V.A. Hospital, and Boston University School of Public Health, Massachusetts
ALICE M.=CLARK, Office of Research and Sponsored Programs, University of Mississippi, Oxford
NORMAN R.=FARNSWORTH, Department of Medicinal Chemistry and Pharmacognosy, University of Illinois
at Chicago
ADRIANE FUGH-BERMAN, Department of Health Care Sciences, George Washington University School of
Medicine, Washington, D.C. (until April 2002).
TED GANSLER, Medical Information Strategy, American Cancer Society, Atlanta, Georgia
PHILIP S.=GUZELIAN, Department of Medicine, University of Colorado Health Sciences Center, Denver
ELIZABETH JEFFERY, Department of Food Science and Human Nutrition, University of Illinois at Urbana
JOSEPH LAU, Division of Clinical Care Research, New England Medical Center, Boston, Massachusetts
LARS NOAH, University of Florida College of Law, Gainesville (until January 2002)
SUSAN S.=PERCIVAL, Department of Food Science and Human Nutrition, University of Florida, Gainesville
CHERYL L.=ROCK, Department of Family and Preventive Medicine, University of California, San Diego, La
Jolla
Consultants
EDWARD A.=BORTNICHAK, Strategic Value Assessment, Sanofi-Synthelabo, New York, New York
KENNETH FISHER, Washington, D.C.
LEWIS A.=GROSSMAN, Washington College of Law, American University, Washington, D.C.
Staff
ALLISON A.=YATES, Study Director
MARILEE K.=SHELTON, Program Officer
ALICE VOROSMARTI, Research Associate
VIVICA KRAAK, Research Associate
SYBIL BOGGIS, Senior Project Assistant
vi
FOOD AND NUTRITION BOARD
CUTBERTO GARZA (chair), Division of Nutritional Science, Cornell University, Ithaca, New York
ROBERT M.= RUSSELL (vice chair), Jean Mayer U.S. Department of Agriculture Human Nutrition Research
Center on Aging, Tufts University, Boston, Massachusetts
VIRGINIA A.=STALLINGS (vice chair), Division of Gastroenterology and Nutrition, The Children's Hospital
of Philadelphia, Pennsylvania
LARRY R.=BEUCHAT, Center for Food Safety and Quality Enhancement, University of Georgia, Griffin
BENJAMIN CABALLERO, Center for Human Nutrition, Johns Hopkins Bloomberg School of Public Health,
Baltimore, Maryland
ROBERT J.=COUSINS, Center for Nutritional Sciences, University of Florida, Gainesville
SHIRIKI KUMANYIKA, Center for Clinical Epidemiology and Biostatistics, University of Pennsylvania
School of Medicine, Philadelphia
LYNN PARKER, Child Nutrition Programs and Nutrition Policy, Food Research and Action Center,
Washington, D.C.
ROSS L.= PRENTICE, Division of Public Health Sciences, Fred Hutchinson Cancer Research Center, Seattle,
Washington
A.CATHARINE ROSS, Department of Nutrition, The Pennsylvania State University, University Park
BARBARA O.=SCHNEEMAN, Departments of Nutrition and Food Science, Division of Clinical Nutrition and
Metabolism, and Office of University Outreach, University of California, Davis
ROBERT E.=SMITH, R.E.Smith Consulting, Inc., Newport, Vermont
STEVE L.=TAYLOR, Department of Food Science Technology, University of Nebraska-Lincoln
CATHERINE E.=WOTEKI, College of Agriculture, Iowa State University, Ames
BARRY L.= ZOUMAS, Department of Agricultural Economics and Rural Sociology, The Pennsylvania State
University, University Park
Staff
ALLISON A.=YATES, Director
LINDA D.=MEYERS, Deputy Director
GERALDINE KENNEDO, Administrative Assistant
GAIL SPEARS, Staff Editor
GARY WALKER, Financial Associate
vii
BOARD ON LIFE SCIENCES
COREY S.=GOODMAN (chair), Department of Molecular and Cell Biology, University of California, Berkeley
R.=ALTA CHARO, Law and Medical Ethics, University of Wisconsin at Madison
JOANNE CHORY, The Salk Institute for Biological Studies, La Jolla, California
DAVID J.=GALAS, Keck Graduate Institute of Applied Life Sciences, Claremont, California
BARBARA GASTEL, Department of Journalism, Texas A&M University, College Station
JAMES M.=GENTILE, Natural Science Division, Hope College, Holland, Michigan
LINDA E.=GREER, Natural Resources Defense Council, Washington, DC
ED HARLOW, Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School,
Boston, Massachusetts
ELLIOTT MEYEROWITZ, Division of Biology, California Institute of Technology, Pasadena
ROBERT T.=PAINE, Department of Zoology, University of Washington, Seattle
GREGORY A.=PETSKO, Rosenstiel Basic Medical Sciences Research Center, Brandeis University, Waltham,
Massachusetts
STUART L.=PIMM, Center for Environmental Research and Conservation, Columbia University, New York
JOAN B.=ROSE, Department of Marine Science, University of South Florida, St. Petersburg
GERALD M.=RUBIN, Howard Hughes Medical Institute, Chevy Chase, Maryland
BARBARA A.=SCHAAL, Department of Biology, Washington University, St. Louis, Missouri
RAYMOND L.=WHITE, DNA Sciences, Inc., Fremont, California
Staff
FRANCES SHARPLES, Director
MARILEE K.=SHELTON, Program Officer
viii
FOREWORD
ix
Foreword
The Committee on the Evaluation of the Safety of Dietary Supplement Ingredients was asked to develop a
framework for use by the U.S. Food and Drug Administration (FDA) to evaluate the safety of dietary supplement
ingredients. It should include, from a science-based perspective, a system for prioritizing review of dietary
supplement ingredients that could be extended to new ingredients as notifications regarding intent to market
were submitted by manufacturers. Although evaluation of data regarding the efficacy of such ingredients to
maintain health is of interest to many, a review of these data was specifically not included in the charge to the
committee. Thus, what follows in this report is a proposed framework for prioritizing and evaluating the safety
of dietary supplements based on existing information available to FDA and others.
The committee is now in the process of evaluating six dietary supplement ingredients in a mock evaluation
following the process outlined in this report. Our expectations is that by (1) the experience of applying the
proposed framework to develop prototype monographs on these ingredients, albeit within the constraints of an
outside organization, and (2) the review of comments solicited from various stakeholders regarding the proposed
framework, the committee will be able to revise and further elaborate the proposed system, resulting in a final,
fully developed framework to provide to FDA.
Although this study is under the primary management of the staff of the Food and Nutrition Board (FNB) of
the Institute of Medicine (IOM), it is being conducted as a collaborative project within The National Academies
by FNB and the Board on Life Sciences (BLS) of the Division of Earth and Life Studies.
The committee was assisted in this challenging first task by the invaluable contributions of a number of
individuals. Christine Lewis Taylor, FDA's Project Officer, met with the committee early in its deliberations. We
appreciated her clear presentation about the committee's task. The committee also recognizes the significant
contributions made by two members of the committee who resigned during the development of the report, Lars
Noah and Adrianne Fugh-Berman; their insights were very valuable to the development of the proposed process.
We also acknowledge the real loss experienced by the committee and its progress in the untimely death of
committee member Dr. Norman Gillis last year as the committee was just beginning this process. Finally, we
gratefully appreciate the assistance of Stephen F.=McNamara, of Hyman, Phelps, and
FOREWORD
x
McNamara, for his technical review of Chapter 1, and of Janice Rice Okita, a new FNB program officer working
on the monograph development phase of this project, for her assistance with the toxicology section in Chapter 4,
Key Factors.
The committee was greatly assisted by the very able work of Marilee Shelton, program officer for BLS,
who has provided significant assistance to the management and conceptual development of the framework; her
efforts to the move the project forward have been key to the process. In addition, Allison Yates, Study Director,
has provided valuable insight and input for accomplishing the task of the committee. We also greatly appreciate
the able and dedicated assistance of Alice Vorosmarti, research associate; Vivica Kraak, research associate, who
joined the project as Alice Vorosmarti went on leave; and Sybil Boggis, senior project assistant. We thank Gail
Spears for her editorial advice, Gary Walker for financial management, and members of IOM's Office of Reports
and Communication for assistance in the production and dissemination of the report. Finally, we would like to
thank the FNB and BLS reviewers, Robert W.=Russell, Tufts University; Robert J.Cousins, University of Florida;
and Linda E.=Greer, Natural Resources Defense Council for their comments on the clarity of the report.
This report has been reviewed in draft form by individuals chosen for their diverse perspectives and
technical expertise, in accordance with procedures approved by the National Research Council's (NRC) Report
Review Committee. The purpose of this independent review is to provide candid and critical comments that will
assist the institution in making its published report as sound as possible and to ensure that the report meets
institutional standards for objectivity, evidence, and responsiveness to the study charge. The review comments
and draft manuscript remain confidential to protect the integrity of the deliberative process. We wish to thank the
following individuals for their review of this report:
Joseph Betz, National Institutes of Health
Joseph Borzelleca, Virginia Commonwealth University
D.=Craig Brater, Indiana University School of Medicine
Steven Dentali, Dentali Associates
Sanford A.=Miller, Virginia Polytechnic Institute and State University
R.William Soller, Consumer Healthcare Products Association
Meir Stampfer, Harvard University
Although the reviewers listed above have provided many constructive comments and suggestions, they were
not asked to endorse the conclusions or recommendations nor did they see the final draft of the report before its
release. The review of this report was overseen by Bernadette Marriott, Burroughs Wellcome Fund, appointed by
the Institute of Medicine, and Catherine Woteki, Iowa State University, appointed by the National Research
Council's Report Review Committee. The coordinator and monitor were responsible for making certain that an
independent examination of this report was carried out in accordance with institutional procedures and that all
review comments were carefully considered. Responsibility for the final content of this report rests entirely with
the authoring committee and the institution.
As chair of the committee, I want to thank my fellow committee members for their commitment to the work
of the committee under a rather demanding time schedule. Their quick and constructive responses to the many
drafts of the report made meeting the deadline possible.
Barbara O.=Schneeman, Committee Chair
CONTENTS
xi
Contents
EXECUTIVE SUMMARY
1
1
INTRODUCTION AND BACKGROUND
13
2
APPROACHES USED BY OTHERS TO CONSIDER DIETARY SUPPLEMENT SAFETY AND
OTHER EXISTING SAFETY FRAMEWORKS
29
3
OUTLINE OF THE OVERALL PROCESS FOR EVALUATION OF DIETARY SUPPLEMENT
INGREDIENTS
39
4
FACTORS CONSIDERED IN SCREENING, SETTING PRIORITIES, AND SAFETY EVALUATION
47
5
FRAMEWORK STEPS ONE AND TWO: SCREENING/FLAGGING AND PRIORITY SETTING
77
6
FRAMEWORK STEP 3: CRITICAL SAFETY EVALUATION OF DIETARY SUPPLEMENT
INGREDIENTS
91
7
ATTRIBUTES AND LIMITATIONS OF THE PROPOSED FRAMEWORK
99
8
DIETARY SUPPLEMENT INGREDIENTS SELECTED FOR PROTOTYPE SAFETY MONOGRAPHS
103
CONTENTS
xii
APPENDIXES
A
Other Approaches to Considering the Safety of Dietary Supplements
106
B
Existing Frameworks or Systems for Evaluating the Safety of Other Substances
116
C
Possible Combinations of Scores
124
D
Table of Food and Drug Administration Actions on Dietary Supplements
138
E
Presenters at the Open Sessions of the Project on the Framework for Evaluating the Safety of Dietary
Supplements
140
F
Biographical Sketches of Committee Members
141
EXECUTIVE SUMMARY
1
Executive Summary
Consumer interest in health and self-care has expanded the market for a wide range of products including
dietary supplements. Consumer use of dietary supplements has grown exponentially in the past decade,
signifying increases for both traditional as well as new uses. As new formulations and products have come on the
market, estimates of total sales have grown to $15.7 billion per year (Blendon et al., 2001; Nutrition Business
Journal, 2000). As with conventional foods, many dietary supplements are probably safe when used as
recommended. However, increased use of supplements, the broad spectrum of products that qualify as dietary
supplements under the Dietary Supplement Health and Education Act of 1994 (DSHEA), and its requirement
that the Food and Drug Administration (FDA) determine what is unsafe without requiring specific information
on safety be presented by manufacturers prior to marketing, make regulation of dietary supplements a sizeable
challenge.
THE COMMITTEE'S TASK
To monitor the continually evolving patterns of dietary supplement use and potential interactions with other
consumed substances, FDA needs a cost-effective and scientifically based approach to considering the safety of
dietary supplements. For these reasons, FDA turned to the Institute of Medicine (IOM) of The National
Academies to provide a framework for evaluating the safety of dietary supplement ingredients. FDA requested
that a committee of experts (1) develop a proposed framework for categorizing and prioritizing dietary
supplement ingredients sold in the United States based on safety issues, (2) describe a process for developing a
system of scientific reviews with specifications for evaluating the safety of dietary supplement ingredients, and
(3) utilize the proposed framework to develop at least six scientific reviews or monographs as prototypes for the
system after release of the proposed framework. The proposed framework is to include a methodology to review
data with regard to the safety of dietary supplement ingredients, taking into consideration methods other expert
bodies have used to categorize and review supplement safety and efficacy issues.
The proposed framework described in this report is now being released for comment and discussion to
interested organizations and individuals; it is intended that at least one open forum will be held specifically to
solicit input about the framework and its process for setting priorities and categorizing dietary supplement
ingredients, as well as about the process for review and
EXECUTIVE SUMMARY
2
evaluation of information in the development of the prototype monographs. Based on a review of comments
received and experience gained from completion of the prototype monographs, the proposed framework will be
modified as appropriate. The revised framework will be released in a final report of the committee. This final
report will also include the six prototype monograph reviews as examples of how the framework as revised can
be implemented.
TABLE ES-1 Current Status of Foods, Drugs, and Dietary Supplements under Food and Drug Administration (FDA)
Regulation
Status
Dietary Supplements Foodsa Food Additives New Drugsb
Premarket approval required
Noc
Nod
Yes
Yes
Risk-benefit analysis conducted by FDA prior to marketing No
No
No
Yes
Postmarket reporting or surveillance by industry required
No
No
Rarely
Yes
FDA
FDA Manufacturer
Manufacturer
Burden of proof for demonstrating safety or lack thereof
a
Foods (including conventional foods and dietary supplements), unlike drugs, are considered to be safe (reasonable certainty of no harm),
and thus risk-benefit analysis is not applicable.
b This description applies to “new” drugs. Many over-the-counter drugs that are not “new drugs” are regulated under FDA's Over-TheCounter Drug Review procedures, which do not provide for postmarketing surveillance.
c A 75-day premarket notification, but not premarket approval, is required for dietary supplements containing ingredients not marketed before
1994.
d In 2001 FDA proposed a rule requiring marketers of food developed through biotechnology to notify the agency at least 120 days before
commercial distribution and to provide information to demonstrate that the product is as safe as its conventional counterpart (FDA, 2001).
BACKGROUND
Current regulatory approaches to safety evaluation of dietary supplements in the United States are a product
of several key pieces of legislation that span from the beginning to the end of the 20th century, culminating in
the passage of DSHEA in 1994. The major controversy in considering the safety of dietary supplements has been
whether supplements should be regulated as if they were conventional foods, food additives, or as drugs; foods
are considered to be safe unless demonstrated otherwise, thus the government bears the burden to prove
conventional foods are unsafe (see Table ES-1).
Since 1938 the drug industry has borne the burden of proof in establishing the safety of new drugs before
they can be marketed, while the burden of establishing a food as unsafe has continued to remain with FDA. The
1938 Federal Food, Drug, and Cosmetic Act, which established the different burdens of proof, did not address
when vitamins, minerals, and botanical products should be regulated as drugs as opposed to foods.
In 1958 the Food Additives Amendment defined food additives and provided that they must undergo a
premarket approval process unless they were considered as generally recognized as safe (GRAS). FDA
attempted to regulate the botanical industry by alleging that individual
EXECUTIVE SUMMARY
3
botanical products were unapproved food additives, an effort eventually struck down by the courts.
BOX ES-1 LEGAL DEFINITION OF A DIETARY SUPPLEMENT AS DEFINED BY THE
DIETARY SUPPLEMENT HEALTH AND EDUCATION ACT OF 1994
The term dietary supplement:
(1)
means a product (other than tobacco) intended to supplement the diet that bears or contains one or
more of the following dietary ingredients:
(A)
(B)
(C)
(D)
(E)
(F)
a vitamin;
a mineral;
an herb or other botanical;
an amino acid;
a dietary substance for use by man to supplement the diet by increasing the total dietary intake; or
a concentrate, metabolite, constituent, extract, or combination of any ingredient described in clause
(A), (B), (C), (D), or (E).
Dietary supplements are further defined as products that are labeled as dietary supplements and are
not represented for use as a conventional food or as a sole item of a meal or the diet. Supplements can be
marketed for ingestion in a variety of dosage forms including capsule, powder, softgel, gelcap, tablet, liquid,
or, indeed, any other form so long as they are not represented as conventional foods or as sole items of a
meal or of the diet (FDCA, as amended, § 402).
In the 1970s FDA tried to implement tighter regulations on vitamin and mineral supplements, but its actions
were restricted by Congress via the 1976 Vitamins and Minerals Amendments. After FDA made another attempt
to enforce stricter adherence to regulations in 1993, Congress acted further to contain FDA's authority by passing
DSHEA in 1994.
DSHEA established the first comprehensive definition of dietary supplements as foods (Box ES-1), along
with legislative language defining procedures and regulations governing their marketing. Specifically, substances
and products on the market in the United States prior to October 15, 1994 could continue to be marketed, but
introduction of new products would require notification by the manufacturer to FDA 75 days prior to marketing.
Most importantly, DSHEA established a regulatory framework for dietary supplements that defines FDA's
authority over these products. It establishes that dietary supplements are to be considered equivalent to foods in
that they are assumed safe unless FDA has evidence that proves otherwise.
It is this postmarket burden of proof that makes FDA's consideration of dietary supplement ingredients
profoundly different from its consideration of substances such as food additives or drugs. Before marketing, food
additives and drugs are required to undergo extensive safety evaluations by manufacturers that must prove them
to be safe under conditions of use (see Table ES-1).
FINDINGS
In preparation for developing a framework and then prototype monographs of six selected dietary
supplement ingredients, the committee was also charged with reviewing methods used by other expert bodies to
categorize and review safety issues related to dietary supplements. The
EXECUTIVE SUMMARY
4
committee reviewed published information about the approaches several organizations have taken to learn more
about the limitations in the approaches, as well as their attributes. In reviewing these frameworks, the committee
noted the following:
• The purpose of the efforts varied substantially from organization to organization, focusing on quality,
efficacy, safety, or a combination of these.
• Most of the approaches were focused exclusively on botanical ingredients, others focused on medicinal
substances. The reviewed approaches did not focus on the safety of dietary supplements of all types.
• The approaches did not develop a systematic method to provide a categorized list of ingredients based
on their need for more immediate attention, although several placed ingredients after review in general
categories such as unsafe, safe, or unsafe for particular populations.
• Often the approaches were not sufficiently detailed or transparent to give a complete picture of the data
considered, the rationale behind the conclusions, and remaining unanswered questions regarding safety.
After reviewing approaches of other groups, the committee's first objective was to develop a clear
understanding of the purpose of the study and the expectations of FDA and those of industry. The second
primary objective was to develop a collective understanding of what was meant by a “framework” and to
identify common characteristics of effective frameworks already in place. To this end, the Committee defined
a “framework” for safety evaluation of dietary supplement ingredients as “the processes by which FDA
can screen, set priorities, and evaluate available information to make regulatory decisions regarding
dietary supplement ingredients.”
In reviewing the methods used by other expert bodies to consider the safety of substances, and in reviewing
the discussions with the sponsors and other interested representatives, the following attributes of an ideal
framework were identified:
• it must be workable and able to be integrated into FDA's program of work;
• it should provide guidance to organizing diverse information already available;
• it should categorize the diverse substances classified as dietary supplements based on a scientifically
valid metric;
• it should establish a database for collection of information regarding potential safety concerns that can
be updated as new information is available; and
• it should provide a method to integrate diverse information into a prioritization scheme so that efforts
and resources can be maximally directed toward those dietary supplement ingredients with the greatest
safety concerns.
Once the definition and attributes of a safety framework were understood, the committee then identified key
factors that could be used in such a framework. Following this, the committee developed a methodology to
screen, set priorities, and then conduct critical evaluations of safety, with the results being collated into a
monograph format. As a result of the review of types of information thought to be available for some dietary
supplement ingredients, “guiding principles” for consideration during all of the steps were established.
EXECUTIVE SUMMARY
5
Finally, the initial steps of the framework were applied to a variety of dietary supplement ingredients. Six
diverse dietary supplement ingredients that would be expected to be flagged in the screening step were identified
to serve as prototypes to test the proposed framework during the second phase of the study. During this phase,
monograph reviews will be developed and put through the final critical safety evaluation step of the proposed
framework.
PROPOSED FRAMEWORK FOR EVALUATING THE SAFETY OF DIETARY
SUPPLEMENT INGREDIENTS
The Proposed Framework for Evaluatiing the Safety Dietary Supplement Ingredients consists of three steps:
Step One, screening/flagging; Step Two, priority setting; and Step Three, critical safety evaluation (See
Table ES-2 and Figure ES-1). Ideally, a critical safety evaluation for each dietary supplement ingredient could
eventually be completed, but to best leverage available resources, it is necessary to determine which supplement
ingredients warrant attention first. The first two steps in the process, screening/flagging and priority setting, are
designed to set priorities for reviewing dietary supplement ingredients based on concern.
Key Factors Used in the Framework
In any scientific evaluation there are different types of data that are useful, or “factors” to consider, when
collecting and sorting information (see Chapter 4). Different factors contribute to each step of the framework to a
different degree, with different sources of information necessary to examine and evaluate the factors in the
various steps of the processes proposed.
One key factor that should contribute to decision making at all three steps of the process is human data.
Additional factors that should be considered are animal data, followed by information about the biological
activity of structurally related and taxonomically related substances, and in vitro evidence of adverse effects.
The potential for interactions among dietary supplement ingredients and other ingested substances or medical
treatments are considered within each of these categories. An additional question considered only in the initial
screening/flag step is whether the ingredient is new to the United States, as defined by DSHEA.
Other important factors integral to the framework are referred to as modifying factors. Whether particular
subpopulations are especially vulnerable to the adverse effects of particular dietary supplement ingredients is
considered with the data for each of the above factors. Second, the overall prevalence of use of the dietary
ingredient in the United States is considered during the sorting process to increase the priority for review within
a priority group.
Step One: Screening/Flagging
The screening process was developed on the premise that it is not feasible for FDA to extensively search for
information about each and every dietary supplement ingredient immediately. Readily available information can
be used to flag substances that warrant further attention, while maintaining enough sensitivity to minimize false
negatives and not omit any items with potential safety concerns.
To flag substances warranting some level of attention, “yes or no” questions were developed to identify
ingredients to undergo Step Two, priority setting:
Ingredients warranting further
investigation are flagged
Goal
FDA or contractor
Human data
Animal data
Biological activity of structurally
related and taxonomically related
substances
In vitro data
Vulnerable group use considered
with other factors
Comprehensive
Request industry data and data from
other stakeholders
Weighting based on evidence of
Comprehensive: totality of evidence
possible risk, potential seriousness
is considered, including data
of harm, and relative importance of requested from industry and other
factor
stakeholders
Table of ingredients sorted into
Monograph AND
priority groups for further evaluation FDA decision for action/inaction OR
Referral to external advisory
committee
FDA
Human data
Animal data
substances
In vitro data
Vulnerable group use (modifies
other factors)
Prevalence of use (modifies priority
ranking)
Literature search is more
comprehensive
Step Three, Part A: Draft Monograph
Preparation and Monograph Review
by the Food and Drug Administration
(FDA)
Ingredients flagged in screening step Ingredients with highest priority
based on Step Two ranking
Step Two: Priority Setting
Monograph with conclusions of
external advisory committee
Totality of evidence; monograph
reviewed and revised
Comprehensive
Public input
Monographed ingredients for which
a decision is not clear cut or for
which further input is desired
External advisory committee
Human data
Animal data
substances
In vitro data
Vulnerable group use (considered
with other factors)
Step Three, Part B: Critical Safety
Evaluation
The term “other concerns,” as described in Chapter 3, encompasses concerns FDA becomes aware of without extensive information searching. These may include concerns expressed by other regulatory
agencies, concerns expressed in secondary literature, or concerns expressed by other organizations.
a
Low level evaluation: is there
evidence suggesting a concern
may exist?
Depth of evaluation
Level of information search Easily obtainable information (see
Table 4–1)
All ingredients are considered
“New” ingredients are
automatically flagged
Completed by
FDA
Factors and modifiers used Human data: serious adverse
events only
Other concerns, a as they come to
FDA's attention
Which ingredients
TABLE ES-2 Overall Framework
Step in the Process
EXECUTIVE SUMMARY
6
FIGURE ES-1 Flowchart of Overall Framework
EXECUTIVE SUMMARY
7
EXECUTIVE SUMMARY
8
1. Has a 75-day new ingredient notification been filed with FDA for the ingredient in question?
2. For the ingredient in question, are there potentially serious1 adverse events in humans reported
through MedWatch, poison control centers, or clinical studies that illustrate a pattern (in terms of the
type of incident reported) that are well-documented in the medical literature, or that may be
plausibly linked to the dietary supplement ingredient? Does the number of serious adverse events
reported in humans appear high compared to the ingredient's prevalence of use? Does it seem
plausible that particular subpopulations are particularly susceptible to serious adverse events?
3. Has the ingredient been brought to FDA's attention because of concerns other than new ingredient
status or human adverse event data described above? A preliminary evaluation of concerns that have
come to FDA's attention will allow FDA to determine which of these ingredients should move into
priority setting.
In keeping with the philosophy that the screening step should be relatively simple and straightforward,
answering these questions does not involve evaluation or weighting of the evidence. A single “yes” to any one
question is sufficient to move the ingredient to the next step.
The goal of the priority-setting process (Step Two) is to identify those dietary supplement ingredients that
require the most immediate attention of FDA for in-depth safety evaluation. The priority-setting process differs
from the initial screening process in four fundamental ways:
•
•
•
•
additional factors are considered;
additional information is obtained;
the evidence of possible risk, as well as the seriousness of potential harm is judged to some degree; and
the different factors are weighted differently, based on importance.
Scoring and Sorting the Data
A sorting matrix is proposed to consider the importance of the information available for each key factor and
to sort the ingredients accordingly. The available data for each of the four key factors (human data, animal data,
biological activity of structurally related and taxonomically related substances, and in vitro data) are examined
for all dietary supplement ingredients that were flagged in the screening process. A judgment is made of both the
potential seriousness of the physiological effect suggested by the data and the strength of the evidence that the
effect may occur. Based on this judgment, the data for each factor are judged and then assigned either a
numerical value of 0 to 3, or NAD (no appropriate data), to indicate the evidence of possible risk and the
potential seriousness of harm suggested by the data. A score of 3 is assigned for each factor where the data
suggest both a potentially serious and very relevant harm and strong
1 The term “serious” is used throughout the report. Serious adverse events are defined in the 1996 Guideline for Good
Clinical Practice issued by the International Committee on Harmonization and endorsed by FDA. A serious adverse event is
an untoward effect that is a death, life-threatening event, initial or prolonged hospitalization, disability, congenital anomaly,
birth defect, or other important medical event.
EXECUTIVE SUMMARY
9
evidence of possible risk, or there is strong evidence suggesting a possible risk of serious drug interaction. A 0 is
assigned when there is strong evidence that there is no potential serious harm. Scores of 1 and 2 are not
explicitly defined but result from a judgment of relative concern, as described in Chapter 5. For each ingredient,
the numerical values for each factor are recorded (see Table ES-3 for a matrix listing fictitious ingredients). The
ingredients in the matrix are then sorted into a list in descending priority, based on the scores, as described in the
next section.
TABLE ES-3 Matrix of Scores Used in Establishing Relative Priority Among Dietary Supplements
Human Data Animal Data Biological Activity of Structurally Related or
Ingredient Name
Taxonomically Related Substances
Yellow plant extract 3
1
2
Vitamin X
2
NAD
2
Animal tissue
2
1
1
a
In Vitro Data
2
NADa
1
NAD=no appropriate data.
Sorting the Ingredients by Scores
After data for an increasing number of dietary supplement ingredients are reviewed and a numerical score is
assigned for each of the key factors, the list of ingredients can be sorted into categories of relative priority (called
Priority Groups) based on the assigned scores.
In the proposed scheme, priority setting is accomplished through a multi-step sorting mechanism that
reflects the importance of the different numerical scores and the hierarchical importance of the different factors
when considering the safety of dietary supplement ingredients. Two of the key factors—human data and animal
data—are placed at the top of hierarchy of data types. Ingredients with scores of 3 in both of these factors are
therefore placed in the highest priority category, Priority Group I, as illustrated in Table ES-4.
Ingredients that were assigned a score of 3 for the human data, but not for the animal data, are categorized
as Priority Group II. Ingredients that were assigned a score of 3 in animal data, but not in human data, are
categorized as Priority Group III. Priority Group IV includes ingredients that were assigned a score of 3 for
either the structure/taxonomy or the in vitro data, but not in the human or animal data. Finally, Priority Group V
includes ingredients that did not receive a score of 3 in any of the key factors.
This priority-setting approach of scoring and then sorting into priority groups allows FDA to consider the
different factors independently and individually for each ingredient, rather than having to compare them to all
the ingredients that are being considered.
Step Three: Critical Safety Evaluation
The screening/flagging and priority-setting steps outlined in the previous sections result in the identification
of priority groups of supplement ingredients based on level of priority for in-depth review. The evaluation
process begins with completing the data collection, as shown in the flowchart (Figure ES-1). Much data will
already have been obtained during the priority-setting step, but efforts should now be expanded to systematically
search for relevant information from
EXECUTIVE SUMMARY
10
additional sources as well. At this stage in the review, there is sufficient concern about the safety of the
ingredient to justify FDA's request for more information to be volunteered by the industry, including data on
safety. All the available information collected should be collated into a “Dietary Supplement Ingredient Safety
Review Monograph,” a task that might be appropriate for FDA to contract out if adequate resources are not
available to prepare it internally.
TABLE ES-4 Matrix for Priority Establishment Based on Factor Analysis
In Vitro
Priority Group Human Data Animal Data Bioactivity of
Structurally Related Data
or Taxonomically
Related Substances
I
3
3
Number of
Combinations
(Total=625)
Characteristics of
Priority Group
25
II
III
IV
100
100
144
Two 3s in first two
factors
3 in human data
3 in animal data
One or two 3s in
structure/ taxonomy
or in vitro factors
No 3s in any key
factor
V
3
3
3
3
256
After preparing the monograph that describes the available information and where information is missing,
FDA should consider the totality of the scientific information collected. FDA should decide, based on the weight
of the evidence, whether information in the monograph is conclusive enough to clearly indicate that action or
inaction is appropriate. If the data are not sufficiently clear to make action or inaction obvious, or for any other
reason FDA deems that external opinions may be valuable, an external advisory committee can be brought in to
work on the issue.
After reviewing the information collected in the monograph and obtained from public comment sessions,
the external advisory committee should revise the monograph to create a picture of the scientific information
available. The advisory committee should evaluate the available scientific information and reach conclusions
where possible, describing what is known about the safety of the ingredient based on the weight of the scientific
evidence. The advisory committee's conclusions should include comments about the risk and hazards that may
be associated with the general population ingesting the ingredient, as well as risks that may be of particular
concern to certain segments of the population. After the advisory committee's conclusions are shared with FDA,
the monograph and the advisory committee's conclusions should be posted on FDA's website.
Guiding Principles to Follow in Evaluating Data in the Framework
“Guiding principles” were developed to address the qualitative aspects of data review in the critical safety
evaluation and for consideration when scoring during the priority-setting step. These guiding principles are:
EXECUTIVE SUMMARY
11
• A credible report of a serious adverse event in humans that is associated with use of a dietary
supplement ingredient raises concern about the ingredient's safety and requires further
information gathering and evaluation. A final judgment on the safety of the supplement
ingredient, however, will require a consideration of the totality of the evidence. Historical use
should not be used as prima facie evidence that the ingredient does not cause harm. It is
appropriate, however, to give considerable weight to a lack of adverse events in large, highquality, randomized clinical trials or cohort studies (prospective or retrospective) that are
adequately powered and designed to detect adverse effects.
• Even in the absence of adverse events in humans, evidence of harm from laboratory animal
studies can be indicative of potential harm to humans. This indication may assume greater
importance if the route of exposure is similar (e.g., oral), the formulation is similar, more than
one species shows the same toxicity, and the general characteristics of good animal studies as
described in Chapter 4 are met. Particular weight is placed on evidence of certain types of
delayed effects that are less likely to be detected in humans, such as cancer, developmental
toxicity (including teratogenicity), and reproductive toxicity.
• The presence of constituents structurally similar to known toxic or potentially harmful
compounds and plants taxonomically related to known toxic plants suggests increased risk, and
therefore higher priority, unless there is evidence that the compound is not toxic or harmful, the
compound is present in concentrations that will not lead to harm, or there is other evidence
supporting the safety of the ingredient.
• In vitro studies can serve as signals of potential harmful effects in humans, but not as independent
indicators of risk of harm unless an ingredient causes an effect that has been associated with
harmful effects in animals or humans, and there is evidence that ingredient or its metabolites
reach physiological sites where harm may occur. Alone, they should serve only as hypotheses
generators and as indicators of possible mechanisms of harm when the totality of the data from
the different factors is considered.
Attributes of the Proposed Framework
There are a number of attributes of the framework proposed, and there are also a few limitations. This
framework integrates a variety of available evidence about safety, balancing the value of different types of
evidence and also integrating usage information to enhance the public-health impact of the work. Using the
framework, FDA can be both proactive and reactive, as well as provide an open and transparent process helpful
to the general public and the industry.
The proposed framework focuses on how to consider the safety of dietary supplement ingredients rather
than offering guidance on how to consider their benefits and role in health. This was a key point of FDA's
request to IOM, and is appropriate since dietary supplements are regulated as foods that must be safe, rather than
as drugs requiring a risk-benefit analysis. A strength of the proposed framework is that it allows the
incorporation of several different types
EXECUTIVE SUMMARY
12
of data that may be available, providing a mechanism to evaluate the totality of the available data. The prioritysetting step weights the different kinds of data available.
When considering the various types of data, the framework outlines how to consider both the strength of the
evidence and the seriousness of harm suggested by the evidence. The evidence of possible risk incorporates both
the methodological quality and the quantity of the available evidence, components that are important when
considering any scientific data. Considering the potential seriousness of harm enables higher priority to be given
to items that are of most concern because of their potential to adversely affect human health.
In addition to the methodology outlined for integrating various types of information, the proposed
framework is also practical because it allows FDA to respond to new information in that the categorization of
priorities easily changes to reflect new data.
Limitations are also inherent in the proposed framework. By definition, this framework cannot be used to
consider the possible benefits of consuming dietary supplements. Another limitation is that, as with any
evaluation of dietary supplement ingredients under the current regulatory scheme, this framework's evaluation of
safety depends on publicly available data or data made available voluntarily by industry. A major component of
this framework in particular is human data, which unfortunately can be highly variable in quality and quantity.
INGREDIENTS FOR PROTOTYPE MONOGRAPH REVIEWS
The second phase of FDA's charge to the Committee on a Framework for Evaluating the Safety of Dietary
Supplements is, after release of the proposed framework for comment, to develop at least six scientific reviews
as prototypes for the system outlined in the framework. The six supplement ingredients selected for the prototype
reviews include the following (in no particular order other than alphabetical): chaparral, chromium picolinate,
glucosamine, melatonin, saw palmetto, and shark cartilage. These six ingredients were selected to fulfill specific
criteria. They include at least one botanical, one vitamin or mineral, one animal product, and one hormonal
product. The selected ingredients also include substances for which a range of different types of available
information and a range in quality of information available is anticipated. Ingredients included are those that
would be expected to be flagged in the screening process and therefore enter the priority-setting step. Based on
very preliminary data, it is also expected that this list includes substances that when initially reviewed in the
priority-setting step, would not all be placed in the top priority category.
SECOND PHASE OF THIS STUDY
The second phase of this study will be to oversee the preparation of prototype monographs on the six
ingredients, following the framework outlined in this report. As outlined in Chapter 6, industry will be requested
to provide safety information about the ingredients undergoing in-depth safety evaluation. Panels will be
organized to review information included in draft monographs and to arrange for public input on the evidence
about safety.
During this phase, comments regarding the proposed framework detailed in this report will be solicited,
reviewed, and revisions made as appropriate, followed by release of a revised framework and the six prototype
monographs as examples of the safety evaluation envisioned.
13
1
Introduction and Background
A significant number of new dietary supplement products have appeared in the marketplace since the U.S.
Congress passed the Dietary Supplement and Health Education Act (DSHEA) of 1994 (P.L. 103–417). At the
time DSHEA was enacted, an estimated 600 U.S. dietary supplement manufacturers produced about 4,000
products (Commission on Dietary Supplement Labels, 1997). The Food and Drug Administration (FDA)
estimates that more than 29,000 different dietary supplements are now available to consumers and an average of
1,000 new products are developed annually (Sarubin, 2000).
Consumer interest in health and self-care has been identified as providing the impetus for the expanded
market of a wide range of products that includes dietary supplements (Prevention Magazine, 2001). Since 1994,
sales of dietary supplements have increased to an estimated $15.7 billion per year (Blendon et al., 2001;
Nutrition Business Journal, 2000). Of this total, it is estimated that Americans spend about $700 million per year
on herbal supplements (Stein, 2000).
Vitamin and mineral supplement use by the U.S. population has been a growing trend since the 1970s
(Bender et al., 1992; Subar and Block, 1990), suggesting that Americans are becoming more receptive to
alternatives to conventional food sources for nutritional health benefits (ADA, 2000). This is despite researchbased dietary recommendations supporting the position that the best nutrition strategy for optimal health and
reducing the risk of chronic disease is to obtain adequate nutrients from a wide variety of foods (Hunt, 1996;
Hunt and Dwyer, 2001).
Within its definition of supplements, DSHEA included ingredients that have not traditionally been
recognized as nutrients or as having nutritional functions, such as botanicals and hormones (Nesheim, 1999). As
with conventional foods, many dietary supplements are considered to be “safe”—that is, there exists a reasonable
certainty of no harm when used as recommended. However, questions have been raised about the safety of some
dietary supplements. When these questions are raised, FDA must rapidly review and further evaluate the safety
of the ingredients. This has created a sizeable regulatory challenge for FDA because of the increased availability
and use of supplements, as well as the broad spectrum of ingredients that qualify as dietary supplements under
the DHSEA legislation.
14
COMMITTEE CHARGE
To expeditiously and efficiently monitor the continually evolving and growing patterns of dietary
supplement use, as well as their potential interactions with other consumed substances, FDA needs a costeffective and scientifically sound approach to consider the safety of dietary supplement ingredients. For these
reasons, FDA turned to the Institute of Medicine (IOM) of The National Academies to propose a framework for
evaluating the safety of dietary supplement ingredients marketed in the United States. Specifically, FDA
requested that an IOM committee (1) develop a proposed framework for categorizing and prioritizing dietary
supplement ingredients based on safety issues, (2) describe a process for developing a system of scientific
reviews with specifications for evaluating the safety of dietary supplement ingredients, and (3) develop at least
six scientific reviews as prototypes for the system. The proposed framework is to include a methodology to
review data with regard to the safety of dietary supplement ingredients, taking into consideration methods other
expert bodies have used to categorize and review supplement safety and efficacy issues. FDA, in its request to
IOM, asked that a framework for setting priorities and evaluating the safety of dietary supplement ingredients be
proposed and released for comment, followed by the development of six prototype monograph reviews using the
procedures outlined in the proposed framework. After development of the prototype monograph reviews, and
based on comments received, the framework is to be revised based on the experience and concerns identified
following its release.
The committee held four meetings while preparing the proposed framework. Three of these meetings
included open sessions so the committee could hear from the sponsor and a number of individuals and
organizations regarding aspects of evaluating the safety of dietary supplements. In addition, representatives of a
number of agencies and organizations that currently evaluate chemical substances for various attributes were
invited to discuss their methodologies and frameworks for approaching reviews of such substances. (See
Appendix F for a list of those presenting at the open sessions of the committee.)
GENERAL BACKGROUND INFORMATION ABOUT DIETARY SUPPLEMENTS
Many of the substances currently marketed as dietary supplements fall into the following categories:
vitamins, minerals, herbs or other botanicals, amino acids, animal-derived products, hormones and hormone
analogs, enzymes, and concentrates, metabolites, constituents, or extracts of these.2 Within each of these
categories, products may be pure single entities of known or unknown chemical components, mixtures in which
all or some components are known, or mixtures of unknown chemical components.
National surveys such as the Third National Health and Nutrition Examination Survey and the 1987 and
1992 National Health Interview Surveys indicate that 40 to 46 percent of Americans reported taking at least one
vitamin or mineral supplement at some time within the month surveyed (Balluz et al., 2000; Slesinski et al.,
1995). Several investigations have explored nutrient supplement (thought to be primarily vitamin and mineral
formulations) use prevalence and trends in the United States (Balluz et al., 2000; Bender et al., 1992; Kim et al.,
1993; Koplan et al., 1986; Slesinski et al., 1995; Subar and Block, 1990), as well as motivations for taking
2 While these are not dietary supplement categories specified by DSHEA, they illustrate the diversity of products currently
marketed as dietary supplements. The 1994 DSHEA description of what constitutes dietary supplements can be found in
Box 1–1.
15
vitamin and mineral supplements (Neuhouser et al., 1999) and characteristics of users versus nonusers (Dwyer et
al., 2001; Ford, 2001; Hartz et al., 1988; Lyle et al., 1998; Nayga and Reed, 1999; Pelletier and Kendall, 1997;
Subar and Block, 1990). However, knowledge about the use prevalence and trends of dietary supplements
(which include nonvitamin, nonmineral supplements) is limited (Radimer et al., 2000). Data from national
surveys collected before the enactment of DSHEA in 1994 may not reflect current supplement consumption
patterns (Costello and Grumpstrup-Scott, 2000), and there are limitations to interpreting user characteristics from
sales data (Radimer et al., 2000).
Existing studies of reported dietary supplement use suggest an association between increased use of dietary
supplements by older individuals and those who report having more healthful lifestyles (Radimer et al., 2000).
The most frequent reason given for dietary supplement use in one national survey was desire for self-care
(Prevention Magazine, 2001). Some consumers report using supplements because of a belief that these products
will ensure good health.
Generally, labeling for a dietary supplement may not claim to “diagnose, mitigate, treat, cure, or prevent a
specific disease or class of diseases” (DSHEA, P.L. 103–417, § 6, 1994; FDCA, 21 U.S.C. § 343(r)(6)(C),
2001). Despite the legal classification, consumers have reported using supplements for very specific purposes
such as treating and preventing illnesses, colds, and flu; increasing “mental sharpness”; and alleviating
depression (Prevention Magazine, 2001). Studies conducted among teenagers suggest that dietary supplements
are used to enhance athletic performance, build muscle, or lose weight (FDA, 1994; Jonnalagadda et al., 2001;
McGuine et al., 2001; Metzl et al., 2001; Smith and Dahm, 2000; Wallace, 2001).
There is also a reported link of more frequent dietary supplement use among Americans with one or more
health problems (Bender et al., 1992), with specific diseases such as breast cancer (Newman et al., 1998), with
higher alcohol consumption, and with obesity (Radimer et al., 2000). Evidence suggests that supplement use may
not be associated with better food intake in all populations, and may differ by ethnicity and across income strata
(Pelletier and Kendall, 1997; Pelletier et al., in press).
Results from a recent national survey of 2,000 adults indicated that 85 percent of respondents had used one
or more dietary supplements in the previous 12 months (Prevention Magazine, 2001). If this sample of U.S.
consumers was representative of the total population, it would translate into more than 44 million consumers
using botanical remedies and an estimated 24 million using specialty supplements (e.g., bee pollen,
dehydroepiandrosterone [DHEA], chondroitin sulfate, kava kava, shark cartilage, and S-adenosylmethionine
[SAMe]) (Prevention Magazine, 2001; Radimer et al., 2000; Ramos, 2000).
Consumer Expectations About Dietary Supplement Safety
The American public may assume that dietary supplements are subject to existing government regulations
similar to those required for over-the-counter (OTC) medications sold without a prescription. In actuality, dietary
supplements are subject to different regulatory requirements in comparison with OTC medications. With the
passage of DSHEA, the burden of proof concerning the safety of dietary supplements was placed on FDA by
requiring FDA to determine that a substance was unsafe rather than requiring a manufacturer to provide data
supporting its safety (Blendon et al., 2001). New dietary supplement ingredients (those not marketed prior to
passage of DSHEA), however, must provide advanced notification to FDA prior to marketing.
16
Only a few national surveys exploring the views and perceptions of Americans regarding dietary
supplements have been conducted. One compilation was based on four national opinion surveys conducted from
1996 to 1999 by the Roper Center for Public Opinion; however, supplement users were not differentiated from
nonusers, thereby limiting the usefulness of the findings (Blendon et al., 2001). Another survey that explored
general patterns of medication use in the ambulatory adult population from 1998 to 1999 also examined use of
vitamins and minerals, as well as herbals and dietary supplements. The Sloan Survey, conducted among 2,590
U.S. consumers, found that 16 percent of prescription drug users also took an herbal or other dietary supplement
(Kaufman et al., 2002). A third telephone survey, conducted by the Princeton Survey Research Associates for
Prevention Magazine, used a nationally representative sample of 2,000 U.S. adults. The results suggested a high
degree of consumer confidence in supplements based on the finding that nearly two-thirds of respondents
believed that herbal supplements were either safe or completely safe (Prevention Magazine, 2001).
Another analysis used two separate data sources that compared the views of dietary supplement users to
nonusers. The first survey, designed collaboratively between researchers at National Public Radio, the Kaiser
Family Foundation, and the John F.Kennedy School of Government, used telephone interviews conducted by the
Princeton Survey Research Associates with 1,200 randomly selected adults in 1999. A second survey was
conducted with 1,013 randomly selected adults (Blendon et al., 2001). Results from the analysis of the two
surveys revealed that regular dietary supplement users reported not discussing dietary supplements use with their
physicians because they believed that the physicians knew little or nothing about these products and may be
biased against them. In addition, many users felt so adamant about the potential health benefits of some of the
products used that they would continue to take them even if the products were shown to be ineffective in
scientifically conducted clinical studies. Despite these beliefs, the analysis also revealed that there was broad
public support for increased government regulation of these products. The majority of those surveyed supported
the following positions:
• FDA should be required to review the safety of new dietary supplements prior to their sale.
• FDA should be granted increased authority to remove from the market products that are shown to be
unsafe.
• Government regulation should have the capacity to ensure that advertising claims about the health
benefits of dietary supplements are truthful (Blendon et al., 2001).
History of the Federal Regulation of Dietary Supplements
A framework for the evaluation of safety of dietary supplement ingredients must be carried out within the
regulatory environment under which the ingredients are to be evaluated. Many herbals and other botanicals have
been used much longer than many other types of dietary supplements currently in use, with ancient cultures
employing them medicinally. People have long used plants and other substances to supplement their diets in an
attempt to prevent or ameliorate specific symptoms. Patent medicines became popular in the 1800s as advertising
increased and the lack of available trained medical personnel and the inability of conventional medicines to
adequately treat many diseases drove consumers to look elsewhere for help. Such products were often secret
formulations and directly marketed to consumers (CDER, 2002).
17
The growing pharmaceutical industry marketed its medicines directly to health professionals. In both cases,
there were few regulations to control unsubstantiated claims to assist the consumer or health professional in
distinguishing between valid and false assertions made by purveyors of the different products. While some
efforts were made by states, federal regulation of these substances and products in the 1800s was essentially
nonexistent (Millikan, 1999).
Food and Drugs Act of 1906
The Food and Drugs Act of 1906, and its companion bill, the Meat Inspection Act of 1906, were the earliest
comprehensive efforts by the U.S. government to bring greater emphasis both to the safety of marketed products
and to the accurate characterization of the benefits derived from their use. The 1906 acts resulted from a
convergence of public, industry, and scientific support that was partially motivated by concern about the safety
of food and patent medicines and widespread fraud in the growing food and drug industry. The triggering event
was the exposure of unsafe conditions in the meat packing industry (Sinclair, 1906). The passing of the 1906 acts
has also been attributed to industry's desire to restore competitiveness to their products in weak foreign and
domestic markets (Barkan, 1985).
The 1906 acts established the broad authority of the federal government to protect the public from
adulterated or misbranded food and drugs, and thus imposed new regulations on the food and drug industries.
Specifically, the laws introduced accountability by requiring that regulated products be labeled accurately and
that they be safe. However, under the Food and Drugs Act, FDA bore the burden of establishing that a food or
drug was unsafe before it could take action against the product.
Federal Food, Drug, and Cosmetic Act of 1938
A movement for increased regulation of ingested substances came about in the 1930s, eventually
culminating in the U.S. Congress passing the 1938 Federal Food, Drug, and Cosmetic Act (FDCA, P.L. 75–717,
52 Stat. 1040 [1938], as amended 21 U.S.C. § 301 et seq., 2001). The FDCA replaced the 1906 law that had
become obsolete due to the technological changes in the production and marketing of food and drugs (FDA,
1981). This new Act created a complex system of federal regulations for foods, drugs, cosmetics, and medical
devices. Some of the more important changes implemented by the FDCA were further introduction of food
standards3 and changing the focus of FDA from that of a policing agency that had been concerned primarily with
confiscating adulterated drugs to that of a regulatory agency involved with the oversight of evaluating new drugs
(Wax, 1995).
The FDCA transferred the responsibility of proving the safety of new drugs to the drug manufacturer and
required manufacturers to submit new drug applications (NDAs) establishing safety to FDA before marketing.4
While FDA no longer had the responsibility of establishing that an unapproved new drug was unsafe before
taking action against it, FDA continued to be
3 Food standards were required to promote honesty and fair dealing in the interest of consumers (FDA, 1981). The
standards consisted of definitions of what constituted a food (e.g., mayonnaise must contain a certain percentage of egg and
oil).
4In 1962, the FDCA was amended to require NDAs to establish the efficacy, as well as the safety, of new drugs.
18
responsible for establishing that a conventional food product was unsafe, as it does to this day5 (Commission on
Dietary Supplement Labels, 1997).
The FDCA contained provisions that applied to foods, drugs, and cosmetics. The application of these
provisions to products containing a vitamin, mineral, or botanical ingredient (whether it was considered a drug or
a food, for example) depended on the product's intended use, as determined usually by the labeling and
advertising claims for the product.
The 1938 Act contains a number of definitions that guide FDA actions according to the regulations derived
from it. One definition of a drug is an article “intended for use in the diagnosis, cure, mitigation, treatment, or
prevention of disease in man or other animals!”; a second definition is “articles (other than food) intended to
affect the structure or any function of the body of man or other animals!”; and a third definition states that a
product is a drug if it is “recognized in the official U.S. Pharmacopeia (USP), official Homeopathic
Pharmacopoeia of the United States, or official National Formulary, or any supplement to any of them.” (FDCA,
P.L. 75–717, 52 Stat. 1040 [1938], as amended 21 U.S.C. § 321(g), 2001).
The 1938 Act contains no specific provisions for vitamin, mineral, or botanical products, except in Section
403(j), which indicates that a food is misbranded if it is claimed to be “for special dietary uses” but its label does
not bear FDA-prescribed statements about its “vitamin, mineral, and other dietary properties” sufficient to
inform the consumer about its value for such uses (FDCA, P.L. 75–717 § 403(j), as amended 21 U.S.C. § 343(j),
2001).
Congress intended that this Section [403(j)] would allow FDA to regulate claims for vitamins, minerals, and
botanical foods more closely than for conventional foods (Pendergast, 1997). However, in enacting Section 403
(j), it has been asserted that FDA was most concerned with the problems of nutritional deficiency and
inadequacy of the diet, and thus did not address either acceptable claims for vitamins, minerals, and botanical
products or when these products should be regulated as drugs as opposed to foods (Pendergast, 1997).
Early Attempts to Regulate the Industry
Eventually FDA did focus attention on claims for vitamins, minerals, and especially botanical products.
FDA began to use extensive litigation directed at claims to regulate the botanical industry in the 1940s. Botanical
products were treated as unapproved drugs not only if they made claims concerning the treatment or prevention
of disease, but also if they made claims concerning the products' effects on the structure and function of the body
—a type of claim foods were allowed to make without being considered drugs. FDA also took action against
manufacturers making therapeutic claims for vitamins and minerals (FDA, 1941).
At that time, FDA did not rigorously apply the FDCA's definition of drugs (those listed in the USP,
National Formulary, or the Homeopathic Pharmacopoeia of the United States), a definition that would have
included most vitamins and minerals and many botanical preparations. In 1944, when FDA charged that certain
vitamin B capsules were misbranded as food and drugs, the courts dismissed the food counts, holding that the
capsules were drugs by definition because vitamin B was listed in the USP (Pendergast, 1997). FDA did not
fully exploit this reasoning in future cases, however, and appeared to abandon this legal theory after several
5However, food colors, binders, and other food additives must be approved for safety or determined to be generally
recognized as safe (GRAS) prior to use (only the dietary supplement ingredient in a marketed supplement is exempted from
food additive regulations), thus technical ingredients are subject to FDA requirements for preapproval.
19
court cases in the 1960s, declaring that a USP listing was insufficient to confer drug status on a product (FDA,
1966).
FDA's focus on regulation of labeling claims it deemed unapproved and indicative of drug status was
closely followed by increased use of publications such as self-help books and magazine articles that explained
claims and intended uses. This approach was a “possible way [for supplement manufacturers] to avoid the FDA
[enforcement]” (Pendergast, 1997). Debate about what constituted “labeling” ensued as FDA attempted to
broaden labeling to include books and other materials. Characterization that this approach restricted the First
Amendment right to free speech resulted in a number of court battles between the 1940s and 1960s.6 The
resulting debate about First Amendment rights and labeling restrictions has been considered by some to be a
significant factor that eventually led to DSHEA as an attempt to resolve the situation (McNamara, 1995). (The
importance of DSHEA is described in greater detail later in the text.)
Food Additives Amendment of 1958
Another major approach instituted by FDA that has been identified as a factor leading to the passage of
DSHEA was its application of the Food Additives Amendment (FAA) of 1958 (P.L. 85–929, 1958) to botanical
products (Kirschman, 1988). The result of FAA was to shift the burden of proof of safety away from FDA for a
substance added to food. Manufacturers were required to obtain premarket approval from FDA unless the
substance at issue could be considered as “generally recognized as safe” (GRAS) or had been sanctioned by
FDA or the U.S. Department of Agriculture prior to 1958. A food additive is defined as “any substance the
intended use of which results, or may reasonably be expected to result, directly or indirectly, in its becoming a
component or otherwise affecting the characteristics of any food!that are not GRAS for intended use” (FDCA,
P.L. 75–717, as amended 21 USC § 321(s), 2001).
FDA instituted action against many popular dietary supplement ingredients based on contentions of
unapproved food additive status. FDA contended that even single ingredient supplements in capsule form
contained unapproved food additives. For example, FDA argued unsuccessfully that black currant seed oil in a
capsule was a food additive (United States v. Two Plastic Drums!Black Current Oil, 984 F.2d 814 [7th Cir.
1993]). Although the courts struck down FDA's effort with black currant seed oil, FDA's application of the food
additive provisions to botanical products and other dietary supplement ingredients has also been considered a
major precipitating factor in the eventual passage of DSHEA (Kirschman, 1998).
1976 Proxmire Amendments
By the 1960s regulation of botanical, vitamin, and mineral supplements was not consistent and was based
on a combination of enforcement and judicial decisions. Court actions required long periods of time and
considerable resources; thus FDA attempted to have broader impact on dietary supplement use by implementing
tighter regulations on vitamin and mineral supplements. In 1973 FDA issued regulations prohibiting certain
representations on vitamin and mineral supplement labels, establishing standards of identity for vitamin and
mineral supplements, and establishing that preparations containing more than 150 percent of the U.S.
Recommended Dietary Allowance (U.S. RDA) per serving were drugs. Both industry and consumers protested
6 See United States v. Detroit Vital Foods, 218 F. Supp. 208 [E.D. Mich. 1963]; United States v. Articles of Drug!Honey,
344 F.2d 288 [6th Cir. 1965]; United States v. Kordel, 164 F2d 913 [7th Cir. 1947], aff'd, 335 U.S. 345 [1948]; United States
v. “Sterling Vinegar and Honey”!Balanced Foods, 338F.2d 157 [2d Cir. 1964].
20
these actions, eventually leading Congress to enact the 1976 Vitamins and Minerals Amendments, also known as
the “Proxmire Amendments,” that prevented FDA from establishing standards limiting the potency of vitamins
and minerals in food supplements or from regulating them as drugs based solely on potency (Pendergast, 1997).
FDA revised its vitamin-mineral regulations in response to this legislation and, after a subsequent court
challenge, ultimately revoked the regulations in 1979 (FDA, 1979).
The Nutrition Labeling and Education Act and Health Claims
With the suppression of FPDA's attempts at more restrictive rulemaking, the realm of products sold as
dietary supplements continued to expand and included botanicals and amino acids, as well as vitamin and
mineral products. This expansion during the late 1970s and the 1980s was accompanied by reports of serious
illnesses attributed to a few of the dietary supplements available at that time. In 1978, for example, an infant with
colic was reportedly given a fatal dose of a potassium chloride supplement based on erroneous advice in a
parenting book, despite medical knowledge that use of such doses of the supplement would induce cardiac arrest
(Wetli and Davis, 1978). In 1989 there were widespread reports that certain tryptophan supplements were
associated with eosinophilia-myalgia syndrome. After considerable in-house research by FDA, evidence
surfaced that the problem might have been associated with the manufacturing process and FDA took actions that
led to the removal of tryptophan from the market.
By this time mounting scientific evidence had led several food companies to start promoting their
conventional foods based on the potential of some of the ingredients or substances found in the food to reduce
the risk of specific diseases. Some have purported that when dietary supplements made similar claims, FDA
treated them more harshly, considering them to be unapproved drugs (Pendergast, 1997). This purportedly
unequal approach toward regulating supplements versus foods supposedly became more evident when in 1987
FDA described criteria for what it would consider as an acceptable health claim (FDA, 1987). These proposed
rules indicated that it might be more difficult for dietary supplement claims to meet FDA's criteria, which could
be interpreted as acknowledging that foods and dietary supplements were not the same (Pendergast, 1997). The
Nutrition Labeling and Education Act (NLEA), which was passed in 1990 (P.L. 01–635), explicitly authorized
“health claims,”7 but did not silence the controversies surrounding the different treatment of supplements and
foods (Pendergast, 1997). Among other things, the NLEA provided that health claims describing the relationship
of a nutrient to a disease or health-related condition were allowed for both traditional foods and dietary
supplements if the claims complied with FDA regulations. FDA was charged with proposing the criteria needed
for foods or supplements to make health claims. Some contend that concerns that FDA would treat supplements
too harshly also contributed to the passage of DSHEA (Pendergast, 1997).
The Dietary Supplement and Health Education Act
In order to provide additional guidance, in 1993 FDA issued an advanced notice of proposed rulemaking
regarding dietary supplements, which was accompanied by the suggestion that some
7 A health claim is a claim that “characterizes the relationship” between a substance in a food and damage, disease, or
dysfunction of the human body. In effect, this allows a claim that otherwise would be regarded as an illegal drug claim when
made for a food.
21
products marketed as dietary supplements might be more appropriately considered under other regulatory
categories. Amino acids, for example, might be considered unapproved food additives, and some botanicals
might be more appropriately considered as drugs (FDA, 1993). Vitamins and minerals were also considered a
potential target of regulation, as FDA suggested that their strength should be limited to levels that approximated
the U.S. RDAs (FDA, 1993).
Industry and consumers reacted quickly and strongly to these potential regulatory restrictions. Extensive
public debate ensued over the importance of dietary supplements in health, consumers' freedom to access
information about supplements, and the controversy over FDA's regulatory approach. As a result, Congress
passed legislation limiting FDA regulation of dietary supplements. This legislation, the Dietary Supplement
Health and Education Act (DSHEA), was signed into law in 1994.
The Regulatory Implications of DSHEA. DSHEA is the most important dietary supplement legislation
enacted to date. In its findings, Congress recognized the wide use of dietary supplements and stated in the
legislation that currently available dietary supplements are generally safe. Passage of DSHEA was based on the
concept that “legislative action that protects the right of access of consumers to safe dietary supplements is
necessary to promote wellness” (DSHEA, P.L. 103–417, § 2, 1994; OIG, 2001). DSHEA established the first
comprehensive definition of dietary supplements (Hoffman, 2001) (see Box 1–1). More importantly, DSHEA
established a new regulatory framework for dietary supplements that limits FDA's authority over these products,
as compared to its authority over food additives and drugs (see Table 1–1 for comparison).
BOX 1–1 LEGAL DEFINITION OF A DIETARY SUPPLEMENT AS DEFINED BY THE DIETARY
SUPPLEMENT HEALTH AND EDUCATION ACT OF 1994
The term dietary supplement:
(1)
means a product (other than tobacco) intended to supplement the diet that bears or contains one or
more of the following dietary ingredients:
(A)
(B)
(C)
(D)
(E)
(F)
a vitamin;
a mineral;
an herb or other botanical;
an amino acid;
a dietary substance for use by man to supplement the diet by increasing the total dietary intake; or
a concentrate, metabolite, constituent, extract, or combination of any ingredient described in clause
(A), (B), (C), (D), or (E).
Dietary supplements are further defined as products that are labeled as dietary supplements and are
not represented for use as a conventional food or as a sole item of a meal or the diet. Supplements can be
marketed for ingestion in a variety of dosage forms including capsule, powder, softgel, gelcap, tablet, liquid,
or, indeed, any other form so long as they are not represented as conventional foods or as sole items of a
meal or of the diet (FDCA, as amended, § 402).
22
TABLE 1–1 Current Status of Foods, Drugs, and Dietary Supplements under Food and Drug Administration (FDA)
Regulation
Status
Dietary Supplements Foodsa Food Additives New Drugsb
Premarket approval required
Noc
Nod
Yes
Yes
Risk-benefit analysis conducted by FDA prior to marketing No
No
No
Yes
Postmarket reporting or surveillance by industry required
No
No
Rarely
Yes
FDA
FDA Manufacturer
Manufacturer
Burden of proof for demonstrating safety or lack thereof
a
Foods (including conventional foods and dietary supplements), unlike drugs, are considered to be safe (reasonable certainty of no harm),
and thus risk-benefit analysis is not applicable.
b This description applies to “new” drugs. Many over-the-counter drugs are regulated under FDA's Over-The-Counter Drug Review
procedures, which do not provide for postmarketing surveillance.
c A 75-day premarket notification, but not premarket approval, is required for dietary supplements containing ingredients not marketed before
1994.
d In 2001 FDA proposed a rule requiring marketers of food developed through biotechnology to notify the agency at least 120 days before
commercial distribution and to provide information to demonstrate that the product is as safe as its conventional counterpart (FDA, 2001).
DSHEA specifically exempts dietary ingredients in dietary supplement products from being regulated under
the category of food additives. Because FDA does not have the authority to consider the dietary ingredients as
food additives, there is no procedure for a manufacturer to obtain premarket approval or establish GRAS status.
Thus, DSHEA eliminates one of the key approaches FDA had taken to restrict the availability of some dietary
supplements, especially multi-ingredient products.
DSHEA also establishes safety standards for dietary supplements. It states that a dietary supplement will be
considered adulterated (i.e., illegal) if it “presents a significant or unreasonable risk of illness or injury under
conditions of use recommended or suggested in labeling” (DSHEA, P.L. 103–417, § 4, 1994, as codified in
FDCA 21 U.S.C. § 342, 2001). Most importantly, it is clear from the law that FDA bears the burden of proof if it
decides to assert that a supplement is adulterated. In summary, while a manufacturer is charged with ensuring the
safety of its products, the manufacturer is not required to reveal the basis of its safety determination unless the
Secretary of the Department of Health and Human Services declares that the product poses an imminent hazard
or FDA brings an action in court alleging the product is adulterated (Box 1–2).
DSHEA and New Dietary Ingredients Marketed After 1994. DSHEA provided additional requirements for
supplements containing “new dietary ingredients” that were not marketed in the United States before October 15,
1994. Such products are deemed adulterated under DSHEA unless the new ingredient has been present in the
conventional food supply in a form in which the food has not been chemically altered, or there is a “history of
use or other evidence of safety establishing that the dietary ingredient when used under the conditions
recommended or suggested in the labeling!will reasonably be expected to be safe” (DSHEA, P.L. 103–417, § 8,
23
1994). In addition, the law requires that to avoid adulteration in the latter instance, the manufacturer or
distributor must provide FDA with the information that is the “!basis on which [it] has concluded that the
dietary supplement containing [the new] ingredient will reasonably be expected to be safe” (DSHEA, P.L. 103–
417, § 8, 1994) at least 75 days prior to marketing the ingredient. If FDA does not reply to the notification within
75 days, the company is free to market the ingredient. FDA may examine the submission and conclude that it
does not provide sufficient evidence to demonstrate that the ingredient is safe. If a manufacturer or distributor
that receives such a response nonetheless chooses to market the product, FDA will consider the product
adulterated and the government may take legal action against it. In any such proceeding, the government bears
the burden of proof.
BOX 1–2 SAFETY STANDARDS FOR DIETARY SUPPLEMENTS AS ESTABLISHED BY DSHEA
Section 4. Safety of Dietary Supplements and Burden of Proof on FDA.
DSHEA amends § 402 (21 U.S.C. 342) by adding the following:
(f) (1) If it is a dietary supplement or contains a dietary ingredient that—
(A)
presents a significant or unreasonable risk of illness or injury under—
(i)
(ii)
conditions of use recommended or suggested in labeling, or
if no conditions of use are suggested or recommended in the labeling, under ordinary conditions of
use;
(B)
is a new dietary ingredient for which there is inadequate information to provide reasonable assurance
that such ingredient does not present a significant or unreasonable risk of illness or injury;
the Secretary declares to pose an imminent hazard to public health or safety, except that the
authority to make such declaration shall not be delegated and the Secretary shall promptly after such
a declaration initiate a proceeding in accordance with sections 554 and 556 of title 5, United States
Code to affirm or withdraw the declaration; or
is or contains a dietary ingredient that renders it adulterated under paragraph [402](a)(1) under the
conditions of use recommended or suggested in the labeling of such dietary supplement.
(C)
(D)
In any proceeding under this paragraph, the United States shall bear the burden of proof on each
element to show that a dietary supplement is adulterated. The court shall decide any issue under this
paragraph on a de novo basis.
(2) Before the Secretary may report to a United States attorney a violation of the paragraph (1)A for a
civil proceeding, the person against whom such proceeding would be initiated shall be given appropriate
notice and the opportunity to present views, orally and in writing, at least 10 days before such notice, with
regard to such proceeding.
SOURCE: FDCA, P.L. 75–717 § 402, as amended 21 U.S.C. § 342(f), 2001.
24
The manufacturer or distributor is responsible initially for determining whether or not an ingredient is new
and thus whether to submit information to FDA before marketing a product containing that ingredient (FDCA,
P.L. 75–717 (1938), as amended 21 U.S.C. § 413 [350b]a, 2001). If FDA disagrees with a company's decision to
market a product without submitting a 75-day notification, the government bears the burden of proof to show
that the substance is a new dietary ingredient requiring such a submission and that the product is therefore
adulterated.
It is important to note that the 75-day notification period is required for new dietary ingredients, but not
new products. A product that is a new combination of ingredients marketed prior to October 1994 does not
require submission of a 75-day notification (FDCA, P.L. 75–717 (1938), as amended 21 U.S.C. § 413 [350b]a,
2001).
Although less relevant to this report, DSHEA also provided for a government commission to consider the
marketing and labeling of dietary supplements. The findings of this commission are described in the Report of
the Commission on Dietary Supplement Labels (Commission on Dietary Supplement Labels, 1997), which
addressed health claims, nutritional support statements, substantiation files for claims and safety, and
publications used in conjunction with sales.
Food and Drug Administration Actions
Dietary supplement manufacturers are generally not required to share their basis for safety determinations
with FDA before marketing. Therefore, FDA determines safety from publicly available information it collects
and from data that it generates in its own laboratories. FDA may not be able to gather enough data to be
confident about the safety of a particular product, but unless it can be proven in court that a substance does not
meet the standard of safety—representing a reasonable certainty of no harm—FDA cannot remove it from the
marketplace. FDA has responded to concerns by warning consumers, health providers, or industry of the specific
concerns. On occasion, FDA actions have led to voluntary product recall by manufacturers (East Earth Herb,
2000; FDA, 2000; Vital Nutrients, 2001). Examples of warnings about specific dietary supplement ingredients
issued in response to a variety of potential health problems identified by FDA as possible concerns are listed in
Appendix D.
Good Manufacturing Practices
As is apparent from the example of contaminated plantain noted in Appendix D, FDA must consider more
than the “inherent” safety of specific dietary supplement ingredients to adequately evaluate the potential for
public health concerns. Because supplement products vary in their quality and composition, the inherent safety
of the ingredients on the label is not the only important variable that is likely to impact the safety of specific
products. Dietary supplement products tainted by improper raw materials, heavy metals, pesticides, and
microorganisms, for example, can be unsafe due to these contaminants. DSHEA provides that FDA may define
current Good Manufacturing Practices (GMPs) for dietary supplement production. GMPs are to address the
aspects of product manufacturing that impact safety of the final product. They would not, however, take into
consideration whether the dietary supplement ingredients themselves are safe—that is the goal of the framework
proposed in this report.
FDA has not yet published proposed or final GMPs for the dietary supplement industry, although such rules
are in development. In this report, the committee is charged to consider aspects of the inherent safety of dietary
supplement ingredients in developing a proposed
25
framework for safety evaluation; FDA is in the process of completing and issuing GMPs to cover safety issues
resulting from other aspects of safety of dietary supplements.
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28
APPROACHES USED BY OTHERS TO CONSIDER DIETARY SUPPLEMENT SAFETY AND OTHER EXISTING SAFETY
FRAMEWORKS
29
2
Approaches Used by Others to Consider Dietary Supplement
Safety and Other Existing Safety Frameworks
The safety and efficacy of dietary supplement ingredients have been considered by a number of
organizations, each of which has a framework or methodology for reviewing dietary supplements. A review of
these methods was the first step in developing a framework useful to the Food and Drug Administration (FDA)
for prioritizing and evaluating the safety of dietary supplement ingredients. Given that these organizations have
considered different aspects of dietary supplement ingredients, it was important to consider the relevance of the
methods or frameworks they have used to organize and review dietary supplement safety issues. Similarly,
frameworks and methodologies have been developed for reviewing the safety of other types of substances: in
foods, in pharmaceuticals, and in the environment. These are also reviewed to identify aspects that might be
applicable to developing a framework for the safety evaluation of dietary supplement ingredients. Based on the
above reviews, discussion in open sessions with many individuals, and the consensus of the committee, attributes
of an ideal framework for setting priorities and evaluating dietary supplement ingredients were developed.
OTHER APPROACHES FOR CONSIDERING DIETARY SUPPLEMENT SAFETY
Several organizations have compiled information on the safety, efficacy, or quality of dietary supplements.
To aid in the development of the framework in this report, samples of these materials were used to construct an
overview of the approaches taken by these organizations. The approaches are described briefly below and in
Table 2–1; more detailed descriptions are provided in Appendix A. The Appendix is based on the information
provided by the organizations or in published descriptions of their approaches. Inclusion on this list does not
constitute endorsement of these sources of information, nor should the list be considered exhaustive of all efforts
to consider safety, efficacy, and/or quality of dietary supplements. The committee chose to focus its review on
approaches that seemed to be the products of organization-sponsored or government-sponsored committee
efforts or a peer-reviewed process. Additional publications, although not reviewed by the committee, might also
be informative (Foster and Tyler, 1999; Grieve, 1996).
FRAMEWORKS
TABLE 2–1 Key Components of Approaches Used by Other Organizations to Evaluate Dietary Supplements
Purpose of Evaluation
Selection and Types of
Product Endpoints
Organization
Substances for Review
Agency for Healthcare
Effectiveness
Variety of types
Summary report
Research and Quality
Safety
Reports done at request of other
agencies and organizations
U.S. Pharmacopeia-National Quality
Variety of types
Monographs in USP or NF
Formulary (USP-NF)
Selection based on:
Safety
Extent of use
Assessment by pharmacognosists
Ability to meet USP-NF
monograph requirements
Evidence of historical use in
traditional medicine
USP Dietary Supplement
Quality
Variety of types
USP certification mark or
Verification Program
Selection is via manufacturer
no mark
sponsorship
American Herbal
Effectiveness
Botanicals commonly used in
Summary monographs
Pharmacopoeia
Quality and analytical
the United States
methods
Selection based on:
Safety
Recommendations of a
prioritization committee
(professional herbalists, herbal
industry, and herbal educators)
Monograph sponsorship
(interested organizations or
companies)
Selection by other groups
American Herbal Products
Safety
Botanical ingredients sold in
Classification as Class 1, 2,
Association
North America
3, or 4
Natural Medicines
Effectiveness Safety
Variety of natural medicines
Summary monographs
Comprehensive Database
sold in the United States and
Safety assessment
Canada
classification:
Likely safe
Possibly safe
Possibly unsafe
Likely unsafe
Unsafe
Effectiveness
Botanicals
Summary monograph
World Health Organization
Safety
Selection based on extent of use,
Quality
worldwide importance, and
availability of data
30
FRAMEWORKS
Organization
Commission E
Purpose of Evaluation Selection and Types of
Substances for Review
Effectiveness
All medicinal plants and
Safety
phytomedicines in the German
marketplace
Health Canada Natural Health
Products Directoratea
Safety
Quality
Effectiveness
European Scientific
Cooperative on Phytotherapy
Effectiveness
Safety
a
Vitamin and mineral
supplements, botanical products,
homeopathic preparations, and
traditional Chinese, Ayurvedic,
and native North American
medicines
Phytomedicines used within the
European Community
31
Product Endpoints
Summary monographs
classified as:
Positive (approved)
Negative (unapproved)
Negative-null (unapproved)
Authorization for sale/product
license
Summary monographs
The Health Canada regulatory framework for natural health products is proposed—not finalized.
Agency for Healthcare Research and Quality
The Agency for Healthcare Research and Quality (AHRQ), a branch of the U.S. Department of Health and
Human Services, is in the process of producing “evidence-based reports” for a limited number of dietary
supplements. The evidence reports include information on safety and efficacy and are developed using a
systematic analysis of the relevant scientific data that employs a weighting/ranking methodology to consider the
data and well-defined criteria for making judgments. AHRQ has contracted this work to several institutions
referred to as Evidence-based Practice Centers. Reports on garlic and milk thistle have been released and a report
on ephedra is in development (AHRQ, 2002). These reports are designed to differentiate the types of evidence
and the strength of the evidence. Due to the exhaustive nature of the reports, they are resource intensive.
U.S. Pharmacopeia-National Formulary
The U.S. Pharmacopeia-National Formulary (USP-NF), a nongovernment, nonprofit organization, develops
monographs on standards of identity, strength, quality, purity, packaging, and labeling of drugs sold in the
United States. These monographs are not focused on the inherent safety of the substance.8 The USP standards are
recognized by Congress in the Federal Food, Drug, and Cosmetic Act of 1938 (21 U.S.C. § 321 et seq.) as the
official compendium of the United States, making its established standards for drugs essentially similar to federal
regulations (USP, 2002a).
8 From 1995 to 1998, USP developed prototype information monographs on several botanicals, in addition to standards
monographs. Subsequently, an information monograph addressing the safety and efficacy of saw palmetto was published on
the Internet in 2000. Dietary supplement information monographs are no longer produced due to lack of funding (Personal
communication, S.Srinivasan, USP, June 19, 2002).
FRAMEWORKS
32
In 1990 USP-NF decided to include monographs for vitamins and minerals and in 1995, after passage of the
Dietary Supplement Health and Education Act, USP-NF decided to include monographs for botanical dietary
supplements (CRN, 1998). The criteria for identification and prioritization of botanicals for monograph
development include absence of safety concerns, extent of use by consumers, interest from regulatory agencies,
positive assessment by recognized pharmacognosists, and suitability of the botanical preparation for meeting
typical requirements of USP-NF monographs (USP, 2000a, 2002b). Depending on its approval status, botanical
monographs are admitted either to the USP or to the NF. A botanical monograph is placed in the USP if the
botanical has an FDA- or USP-approved use. Otherwise, it is placed in the NF. Monographs are not developed
for botanical dietary supplements that the USP believes may be associated with a significant safety risk (USP,
2000a, 2002b).
U.S. Pharmacopeia Dietary Supplement Verification Program
Distinct from its development of the USP-NF monographs, USP launched the Dietary Supplement
Verification Program (DSVP) in November 2001. The program identifies dietary supplement products that
contain all the ingredients listed on their product labels. Manufacturers sponsor products that are tested and
reviewed by USP; if the product meets the DSVP requirements, the product will be granted a USP certification
mark. This mark is intended to signify that the product (1) contains the ingredients stated on the label in the
declared amount and strength, (2) meets stringent standards for product purity, (3) meets specified limits on
known contaminants, and (4) has been manufactured under good manufacturing practices according to the USPNF General Chapter on Manufacturing Practices for Nutritional Supplements and the FDA's Advance Notice of
Proposed Rulemaking for good manufacturing practices (Personal communication, S.Srinivasan, USP, February
14, 2002; USP, 2001). The DSVM certification mark is not intended to imply safety or efficacy of dietary
supplement ingredients.
Other organizations are also undertaking similar efforts to verify label contents, such as ConsumerLab
(http://www.consumerlab.com/) and the National Science Foundation International (http://www.nsf.org/
consumer/consumer_dietary.html).
American Herbal Pharmacopoeia
The American Herbal Pharmacopoeia (AHP), a nonprofit organization, develops monographs on the
quality, effectiveness, and safety of botanical medicines commonly used in the United States. The monographs,
developed for Ayurvedic,9 Chinese, and Western botanicals, include information on traditional use and
information from scientific sources (CRN, 1998). Botanicals are selected for monograph development based on
judgment about the extent of use, the unique value of the botanical, and sponsorship by other interested
organizations or companies (AHP, 2002).
In preparing the monographs, literature searches are conducted in order to review reported side effects,
contraindications, and negative interactions of a botanical. AHP monographs are relatively detailed compared to
monographs produced by other organizations. They are released individually as they are completed; 12 have
been released since 1994 (AHP, 2002).
9 Ayurvedic is a complex system of health care that includes diet and lifestyle practices (i.e., meditation, yoga, and herbs)
in order to maintain the body's equilibrium. Ayurvedic medicines are derived from plants and are used in conjunction with
modern medicine for health maintenance and restoration (Chopra and Doiphode, 2002).
FRAMEWORKS
33
American Herbal Products Association
The American Herbal Products Association (AHPA), a national trade association for the herbal products
industry, published The Botanical Safety Handbook in 1997. This book reviewed approximately 500 herbs that
were on the market in the United States (McGuffin et al., 1997). The focus of the reviews in this book is on
safety, and entries include data on human and animal toxicity, traditional use, regulatory status in various
countries, and current use of herbs in the United States, China, India, Europe, and Australia. The AHPA safety
classification system consists of four safety classes: Class 1 botanicals that can be safely consumed when used
appropriately, Class 2 botanicals for which certain restrictions apply, Class 3 botanicals for which significant
data exist to recommend special labeling, and Class 4 botanicals for which there is insufficient data for
classification.
Natural Medicines Comprehensive Database
The Natural Medicines Comprehensive Database (NMCD) is published by Pharmacist's Letter and
Preserver's Letter. This database reviews many “natural medicines” on the market in North America, reviewing
safety and efficacy for a large number of dietary supplement ingredients. Information on the different substances
reviewed is available by subscription online and in printed version (NMCD, 2002). According to the
organization, the safety evaluation relies primarily on human data, and animal data are rarely used (Personal
communication, P.Gregory, NMCD, November 21, 2001). Each product is rated as: (1) likely safe (general
agreement among reliable references that the product is safe when used appropriately, or a governmental body
has approved its use), (2) possibly safe (product might be safe when used appropriately or there are human
studies that report no serious adverse effects), (3) possibly unsafe (some data suggest that product use might be
unsafe), (4) likely unsafe (agreement among reputable references that the product can be harmful or reliable
reports of harm), or (5) unsafe (general agreement among reliable references that the product should not be used,
reliable reports of clinically significant harm, or safety warnings issued by a reliable agency).
World Health Organization
The World Health Organization (WHO) has developed international specifications for the most widely used
medicinal plants, a number of which are also used as dietary supplements in the United States. WHO published
its first volume of 28 monographs on selected medicinal plants and is in the process of publishing two additional
volumes. The monographs contain information on the safety, effectiveness, and quality control of botanical
medicines (WHO, 1999). Specifically, they present descriptive information, purity tests, chemical constituents,
medicinal uses, clinical studies, pharmacology, contraindications, warnings, precautions, adverse reactions, and
posology. The medicinal plants in the compilation are not categorized on the basis of safety.
Commission E
The Commission E was a 24-member committee established in 1979 by the German Minister of Health to
review botanical drugs and preparations from medicinal plants. Over a period of about 15 years Commission E
reviewed more than 300 botanicals used in German folk medicine for both safety and effectiveness using
scientific literature, unpublished proprietary data
FRAMEWORKS
34
submitted by manufacturers (chemical, toxicological, pharmacological, and clinical testing data), summaries
produced by an umbrella organization of approximately 120 pharmaceutical manufacturers, and public input
(Blumenthal, 1998; Personal communication, H.Schilcher, Commission E, March 19, 2002). The published
monographs do not include references and are relatively short. Each monograph provided one of three approval
ratings for the substance reviewed: (1) positive (approved—substance is considered reasonably safe when used
according to the dosage, contraindications, and other warnings specified in the monograph), (2) negative
(unapproved—safety concerns outweigh the potential benefits of a substance), or (3) negative-null (unapproved
—no risk was found, but also no substantiation of efficacy). The Commission E monographs are published in
German, and the American Botanical Council has published them in English (Blumenthal, 1998). Additional
information about Commission E is included in Appendix A.
Health Canada Natural Health Products Directorate
In Canada vitamin and mineral supplements, botanical products, homeopathic preparations, and traditional
Chinese, Ayurvedic, and native North American medicines are considered to be natural health products (NHPs).
At present, these products are regulated as either foods or drugs.
In response to consumer demand both for enhanced access to natural health products and for assurances of
safety and quality, the Natural Health Products Directorate was established within Health Canada. The
Directorate has developed a proposed regulatory framework for NHPs, which would be considered a subset of
drugs under the Food and Drugs Act. The NHP Regulations were published for comment in December 2001
(Department of Health, 2001).
The main components of the NHP Regulations are definitions and requirements for product licensing, site
licensing, good manufacturing practices, clinical trials, packaging, labeling, and reporting of adverse reactions.
Under product licensing, each NHP sold in Canada will undergo an assessment before it is authorized for sale.
The application for a product license would be required to provide specific information about the NHP, including
the quantity of medicinal ingredients it contains, the specifications, the intended use or purpose, and supporting
safety and efficacy data. Most relevant to the consideration of dietary supplement ingredient safety, the
directorate has not released standards of evidence for safety for public comment.
European Scientific Cooperative on Phytotherapy
The European Scientific Cooperative on Phytotherapy (ESCOP) is an umbrella organization of national
associations for phytotherapy from countries both within and beyond the European Union. The Scientific
Committee of ESCOP, a subgroup of delegates from participating member countries, has created monographs on
the medicinal uses and safety of medicinal plants widely used in Europe (information on quality is not included).
The monographs are published as fascicules, each containing 10 monographs; 6 fascicules on 60 botanicals have
been completed (ESCOP, 2001).
The Physician's Desk Reference for Herbal Medicines and the Physician's Desk Reference
for Nutritional Supplements
In 1998 the Physicians' Desk Reference (PDR) organization broadened its scope from producing a widely
used collection of information on prescription drugs by also producing a
FRAMEWORKS
35
collection of information on botanical medicines. This publication was the first edition of the PDR for Herbal
Medicines, which provides monographs for approximately 700 medicinal herbs. The monographs contain
information on efficacy, safety, potential interactions, precautions, adverse reactions, and dosage. For 300 of
these monographs, the findings and assessments were taken from the German Commission E report. Other
monographs, as well as the reports of another PDR publication, the PDR for Nutritional Supplements, do not
appear to be the products of the type of committee effort or to involve the type of peer-review process envisioned
as ideal by the committee.
ANALYSIS OF DIFFERENT APPROACHES TO DIETARY SUPPLEMENT EVALUATION
By reviewing the approaches other groups have taken to consider dietary supplements, the observations that
follow about positive and negative attributes of each approach have influenced the development of the proposed
framework and system for preparing safety monographs. The type of information evaluated and the purpose of
the review varied substantially from organization to organization. Most notably, the USP verification program
focused on quality, specifically determining if the ingredients in a product were prepared according to good
manufacturing practices, and verifying that the label matched the contents. Although USP indicated that it would
consider whether a substance was safe in deciding whether or not to accept it into the program, there seemed to
be less methodical emphasis on the inherent safety of the ingredients. Several other organizations placed
emphasis on whether the ingredient was efficacious—a worthy objective, but one that fell outside of this
committee's charge. Most of the approaches reviewed were focused exclusively on botanical ingredients or
products, rather than on dietary supplements of all types. The charge to this committee was to include all types of
dietary supplements in its efforts.
Perhaps most notably, the approaches considered did not describe a systematic method of determining
which ingredients needed immediate attention first, a key component of the PDA's charge to the committee.
AHPA's Botanical Safety Handbook, the Natural Medicines Comprehensive Database, and the Commission E
monographs are three examples of monograph collections that did sort ingredients into several categories (e.g.,
approved, unapproved, possibly safe). These approaches, however, sorted ingredients into several categories
after reviewing collected data, rather than sorting all ingredients by relative priority before undertaking an
exhaustive evaluation of the data—as the proposed framework is charged with accomplishing.
A number of the sample monographs considered were not sufficiently detailed or adequately transparent to
give a complete picture of the data types and sources considered, the rationale behind the conclusions, and/or the
remaining unanswered questions about safety. Monographs from several organizations were brief, without an
adequate description of the different types of available data. Without substantial detail in the monograph, it was
not always clear as to how or why a conclusion about the safety of the ingredient was reached.
Understandably, considering the “weight of the evidence” requires expert judgment to a certain degree, but
it was not always apparent what role expert opinion and experience played. The information that forms the basis
for the Commission E monographs, for example, is kept confidential and includes proprietary data. In the
committee's judgment, it is important that the process be transparent and the bases of judgments be clearly
described and consistently applied to the fullest extent possible, including providing opportunities for public
input from industry,
FRAMEWORKS
36
scientists, and other interested parties. Also important is a description of where the scientific data may be
difficult to interpret and where questions about safety remain unanswered.
Another observation is that most of the reviews focused on ingredients, rather than on specific products or
combinations of ingredients. An exception is that the USP verification program, which focuses on specific
products because USP is paid to look at specific products by manufacturers. Commission E is another exception
—it considered the safety of fixed combinations of botanical products, an important approach given the
widespread marketing of combinations (Blumenthal, 1998). Similarly, analysis of specific products was outside
the committee's charge—it was to focus instead on how to consider the safety of different dietary supplement
ingredients and to note how to approach a product containing a combination of ingredients.
ATTRIBUTES OF AN IDEAL FRAMEWORK FOR EVALUATING DIETARY SUPPLEMENTS
There are numerous frameworks in place that FDA and other organizations can use to evaluate the safety of
substances to which humans may be exposed. Assessment of the scope, characteristics, and processes used for
other substances can aid in the development of a workable framework for dietary supplement safety evaluation.
The committee considered frameworks FDA already had in place to evaluate food additives and
pharmaceuticals, as well as the mechanisms other organizations use in working with FDA when considering the
safety of cosmetic ingredients, food additives generally regarded as safe (GRAS), and nutrients. The
Environmental Protection Agency has also developed a system for considering possible human and
environmental impacts of toxic substances. Table 2–2 provides a brief summary of the nondietary supplement
frameworks considered; more detailed summaries of the different approaches, as described by the organizations,
are in Appendix B.
In considering frameworks used to evaluate the safety of substances other than dietary supplements, the
committee developed an understanding of different types of “frameworks” and how they differed from other
methods that might be used to evaluate dietary supplements. To this end, the committee developed a definition of
a “framework” for safety evaluation of dietary supplement ingredients as follows: “The processes by which FDA
can screen, categorize, and evaluate available information to make scientifically documented regulatory
decisions regarding dietary supplement ingredients for consumers.” In reviewing the methods used by other
expert bodies to consider dietary supplements and in reviewing the discussions with the sponsors and other
interested representatives, the following attributes of an ideal framework were identified:
• it must be workable and able to be integrated into the agency's program of work and resources available;
• it should provide guidance to organizing diverse information already available;
• it should categorize the diverse substances classified as dietary supplements based on a scientifically
valid metric;
• it should establish a database for collection of information regarding potential safety concerns that can
be updated as new information is available;
FRAMEWORKS
TABLE 2–2 Safety Review Systems for Nondietary Supplement Substances
Organization
Type of Organization
Purpose of Review
Premarket safety evaluation
Food and Drug Administration/ Government
of food ingredients/food
Center for Food Safety and
additives
Applied Nutrition
Safety evaluation of food
additives/food ingredients
generally recognized as safe
(GRAS) in 1972
Safety evaluation and
determination of GRAS
status of flavor ingredients
Safety assessment of
cosmetic ingredients
Premarket evaluation and
approval of new drugs
Over-the-counter (OTC)
Drug Review to establish
conditions under which OTC
drugs would be considered
generally recognized as safe
and effective (GRAS/E)
Regulation of entry and use
of new chemicals in the
marketplace; assessment of
human and environmental
risk of new chemicals
Determination of the
Tolerable Upper Intake Level
(UL) for nutrientsb
Endpoints
Approved
Approval with limitations
Interim approval
Disapproval
Nongovernment/ nonindustry Continue as GRAS
Select Committee on GRAS
Continue as GRAS with
Substancesa
limitations
Further testing required
Evidence of adverse effects
—may remove GRAS status
if safety not established
Remove GRAS status
Flavor and Extract
Industry
GRAS status
Manufacturers Association
Not GRAS
(FEMA) Expert Panel
Insufficient data to
determine GRAS status
Cosmetics Ingredient Review Industry
Safe as used
Program
Safe with qualifications
Unsafe
Insufficient data
Food and Drug Administration/ Government
Approved
Center for Drug Evaluation
Not approved
and Research
Food and Drug Administration Government
Category I (GRAS/E)
Category II (not GRAS/E or
unacceptable indications)
Category III (insufficient
data)
Environmental Protection
Agency New Chemicals
Program
Government
No action taken to regulate
the chemical
More testing needed
Institute of Medicine/Food and Nongovernment/ nonindustry UL
Nutrition Board
Scientific evidence
insufficient to set UL
a
Source: Select Committee on GRAS Substances (1982).
Note that nutrients are in many cases dietary supplements or dietary supplement ingredients; this safety framework, however, only applies
to nutrients and recognized food components thought to play a role in health.
b
37
FRAMEWORKS
38
• it should provide a method to integrate diverse information into a priority-setting scheme so that efforts
and resources can be maximally directed toward those dietary supplement ingredients with the greatest
safety concerns; and
• it should provide a mechanism for public input.
Once the definition and key attributes of a safety framework were understood and the committee had an
understanding of approaches taken by other expert groups, the committee then developed a framework focused
on the safety of dietary supplements. This approach is outlined briefly in the following chapter, with additional
detail in succeeding chapters.
REFERENCES
AHP (American Herbal Pharmacopoeia). 2002. American Herbal Pharmacopoeia and Therapeutic Compendium: Standards of Analysis,
Quality Control, and Therapeutics. Online. Available at http://www.herbal-ahp.org/. Accessed June 19, 2002.
AHRQ (Agency for Healthcare Research and Quality). 2002. Evidence-based Practice Centers. Online. Available at http://www.ahrq.gov/
clinic/epc/. Accessed June 17, 2002.
Blumenthal M, ed. 1998. Therapeutic Guide to Herbal Medicines. The Complete German Commission E Monographs. Austin, TX: American
Botanical Council.
Chopra A, Doiphode VV. 2002. Ayurvedic medicine. Core concept, therapeutic principles, and current relevance. Med Clin North Am 86:75–
89, vii.
CRN (Council for Responsible Nutrition). 1998. Reference on Evaluating Botanicals. Washington, DC: CRN.
Department of Health. 2001. Natural health products regulations. Canada Gazette, Part I 135:4912–4981.
ESCOP (The European Scientific Cooperative on Phytotherapy). 2001. Publications. ESCOP Monographs. Online. Available at http://
www.escop.com/publications.htm. Accessed November 12, 2001.
Foster S, Tyler VE. 1999. Tyler‘s Honest Herbal. A Sensible Guide to the Use of Herbs and Related Remedies. 4th ed. New York: Haworth
Herbal Press.
Grieve M. 1996. A Modern Herbal. New York: Barnes and Noble.
McGuffin M, Hobbs C, Upton R, Goldberg A. 1997. American Herbal Product Association's Botanical Safety Handbook. Boca Raton, FL:
CRC Press.
NMCD (Natural Medicines Comprehensive Database). 2002. About the Database. Online. Available at http://www.naturaldatabase.com/
aboutdb.asp. Accessed January 7, 2002.
Select Committee on GRAS Substances. 1982. Insights on Food Safety Evaluation. Rockville, MD: Life Sciences Research Office.
USP (The United States Pharmacopeia). 2001. USP Board of Trustees Agrees to Continue Proceeding with Pilot Program for Dietary
Supplement Verification. Online. Available at http://www.usp.org. Accessed October 31, 2001.
USP. 2002a. USP 25-NF 20. Rockville, MD: United States Pharmacopeial Convention, Inc.
USP. 2002b. USP Fact Sheet. Online. Available at http://www.usp.org. Accessed June 18, 2002.
WHO (World Health Organization). 1999. WHO Monographs on Selected Medicinal Plants, Volume I. Geneva: WHO.
OUTLINE OF THE OVERALL PROCESS FOR EVALUATION OF DIETARY SUPPLEMENT INGREDIENTS
39
3
Outline of the Overall Process for Evaluation of Dietary
Supplement Ingredients
PROPOSED FRAMEWORK FOR EVALUATION OF DIETARY SUPPLEMENT
INGREDIENTS
The Food and Drug Administration (FDA) asked the Institute of Medicine to propose a safety framework
that would assist it in overseeing the safety of dietary supplement ingredients. In an ideal situation, FDA would
be able to immediately undertake a full safety evaluation for every supplement ingredient. Since this is not
possible, a process must be implemented to determine which supplement ingredients warrant the highest priority
for review.
This report outlines a three-step framework for considering the safety of dietary supplement ingredients.
The first two steps in the process, “screening/flagging” and “priority setting,” are designed to categorize dietary
supplement ingredients based on theoretical or possible concern, and therefore the immediacy of the need for indepth evaluation of safety, the third step of the process.
For the purposes of describing the proposed process, it is convenient to think of the overall framework as
three distinct phases, separating the screening and priority-setting phases into two distinct steps in the
framework, with the third step being a critical in-depth review. The first step in the process, screening/flagging,
is essentially a beginning point that incorporates the factors that will bring an ingredient to the attention of FDA
and will indicate whether the material should immediately be examined more closely. This step is important
because it is not feasible initially to research the information necessary for priority setting for the entire universe
of dietary supplement ingredients. Over time, it is likely that steps one and two will be viewed as one ongoing
system. The priority-setting system will determine which ingredients require a full safety evaluation first and can
be done on an on-going basis once an ingredient is flagged in the screening step. After dividing flagged
ingredients into priority categories for further evaluation, the third step—in-depth safety evaluations of highest
priority ingredients—can be completed.
Ingredients versus Products
It is important to note that although dietary supplement products are the substances sold on the market, this
framework is designed to consider the safety of dietary supplement ingredients. For the purpose of this
framework, botanical ingredients are defined as the plant parts (e.g., seed, root, leaf) rather than the many
individual chemical compounds contained in a plant. Although this framework focuses on identifying and
reviewing ingredients with inherent safety concerns, it is very important to remember that all products containing
a particular ingredient are not likely to
40
have equivalent safety profiles. As discussed in the following paragraphs, differences in safety profiles may exist
because the products contain different amounts of an ingredient, there are differences in bioavailability (the
degree to which a substance becomes available to the target tissue after administration), there are differences in
the amounts or presence of other substances (including contaminants), or the products are sold in combination
with different ingredients.
Substantial variation can exist among the different brands of products purportedly containing a given
dietary supplement ingredient (Foreman, 2000; Howe, 2000) due to lack of standardization. Products labels may
claim that products are standardized to contain a particular amount of a substance. Several reports of product
analyses, however, suggest that product labels may be inaccurate—that products may contain significantly
higher or lower amounts of substances than indicated on the label (Green et al., 2001; Hamilton-Miller et al.,
1999; Kamber et al., 2001). While a number of reports have suggested that substances do not contain the
substances purported on the label, reports of labeling discrepancies with several botanicals have been disputed on
the basis that laboratories used different analytical methods or measured different chemical markers that may not
be relevant (Betz et al., 1995; Marrone, 1999). The eventual development of standards may address this problem.
In addition to differences in the amount of a substance contained in a product, significant variation may
exist in bioavailability. Variability in bioavailability may result from differences in manufacturing and
formulation that affect how much of a substance is absorbed. For example, dissolution maybe incomplete, or
even if the ingredient's dissolution is complete, absorption may be incomplete if it is degraded in the intestinal
fluid or it does not undergo active or passive transportation out of the intestinal mucosa. Dietary supplements
may be delivered in matrices (tablets, capsules, etc.) that impact dissolution and absorption, or they may contain
ingredients that change absorption and other aspects of bioavailability (Chambliss, 2001).
Quality control guidelines for many ingested substances are described by current Good Manufacturing
Practices (GMPs). As described in Chapter 1, FDA has not yet published proposed or final GMPs for the dietary
supplement industry. Quality control variables that can impact the safety of dietary supplement products include,
but are not limited to, contamination by heavy metals, contamination by harmful microorganisms, contamination
by pesticides, misidentification of raw plant ingredients, and improper storage. GMPs should provide guidance
in a number of these areas (CFSAN, 2000; FDA, 1997).
In addition to variations in products containing a particular supplement ingredient, many products sold
today are “combination products” that are mixtures of more than one dietary supplement ingredient. These
products raise another set of safety concerns because mixtures can have safety profiles different than the summed
effect of discrete ingredients. There is a potential for interaction among ingredients, and even mixtures
containing the same dietary supplements may differ in dose and ratio of components. Although combination
products can produce effects distinct from the individual ingredients, a first approximation of a combination
product's safety can come from examining the safety of the component ingredients. A combination product
containing ingredients that individually are not considered safe is likely to demonstrate some of the same safety
concerns as the individual ingredients.
Even if no single ingredient raises safety concerns, MedWatch and other information sources should be
monitored for clusters of serious adverse events and other possible indicators of problems related to specific
combination products. For example, when data suggest that interactions between individual supplement
ingredients may be associated with adverse effects, combination products that contain these interacting
ingredients warrant particular attention. If
41
potential interactions or clusters of serious adverse events from particular combinations come to FDA's attention,
then the combination product itself should undergo the screening/flagging and priority-setting steps.
In the case of most combinations, it is expected that more data will be available about the safety of the
individual ingredients than about the safety of the combination. If a review raised questions about the
combination of kava kava, Saint John's wort, and passionflower, for example, the initial approach would be to
consider the safety of kava kava, Saint John's wort, and passionflower individually to determine if any of these
three ingredients were individually thought to be of potential concern from a safety perspective. If any of these
individual botanicals were considered unsafe, then the combination product should also be considered unsafe. If
none of the three ingredients alone had raised safety concerns, then it would be appropriate to monitor the
literature, the MedWatch database, and other sources of information for clusters of adverse events or other
indications that harmful effects might be associated with the combination. In the case of popular combinations of
substances, it is possible that a significant amount of data about the safety of the combination will be available,
perhaps even more than is available on the safety of the individual substances (the combination of glucosamine
and chondroitin sulfate maybe such an example). In this case, it may be appropriate to consider the safety of the
combination itself, in addition to the safety of the individual ingredients. If safety concerns have been raised for
an individual ingredient, then these concerns should generally not be considered as mitigated when the ingredient
is combined or used in combination with another ingredient.
In summary, this framework focuses on ingredients rather than products, but the variability among products
necessitates that FDA consider the safety of products as well. Regular monitoring of MedWatch and other
information sources will be necessary to detect indications of serious adverse events possibly related to specific
brands of products.
Initiation of the Process
The three steps of the proposed framework are outlined in Table 3–1 and Figure 3–1. Step One is the initial
screening/flagging process; Step Two, the priority-setting process; and Step Three, the evaluation process. The
stepwise framework is important, but it is recognized that before FDA can get started with the framework, it
needs an initiation process to start screening the large list of dietary supplement ingredients currently on the
market. Several options for this initiation point were considered. It is possible to start by examining:
• The number of serious adverse events reported. MedWatch is a system for collecting adverse events.
While anyone is free to file a MedWatch report, a sizeable portion of contributors to MedWatch are
members of the medical community. The MedWatch system could therefore form the basis for concern
about the safety of particular ingredients (or products). That is, the framework process could be initiated
by first considering ingredients with a greater number of reported serious adverse events. The major
disadvantage of this approach is the incomplete nature of the reports and the limited number of reports
to MedWatch (GAO, 1997).
• A priority list prepared by experts. A group of several experts in the field could, within a day, provide a
list of the top ingredients causing the most concern in their opinion. It is proposed that one expert would
have a background in botanicals (e.g., a pharmacognosist), one would be a physician practicing
alternative medicine, and one would be a nutritional pharmacologist or toxicologist. A key advantage of
this method is that it would have a high probability of identifying most ingredients with any significant
concern prior to collection and review of
Ingredients warranting further
investigation are flagged
Goal
FDA or contractor
Human data
Animal data
substances
In vitro data
Vulnerable group use considered
with other factors
Comprehensive
Request industry data and data from
other stakeholders
Weighting based on evidence of
Comprehensive: totality of evidence
possible risk, potential seriousness
is considered, including data
of harm, and relative importance of requested from industry and other
factor
stakeholders
Table of ingredients sorted into
Monograph AND
priority groups for further evaluation FDA decision for action/inaction OR
Referral to external advisory
committee
FDA
Human data
Animal data
substances
In vitro data
Vulnerable group use (modifies
other factors)
Prevalence of use (modifies priority
ranking)
Literature search is more
comprehensive
Step Three, Part A: Draft Monograph
Preparation and Monograph Review
by the Food and Drug Administration
(FDA)
Ingredients flagged in screening step Ingredients with highest priority
based on Step Two ranking
Monograph with conclusions of
external advisory committee
Totality of evidence; monograph
reviewed and revised
Comprehensive
Public input
Monographed ingredients for which
a decision is not clear cut or for
which further input is desired
External advisory committee
Human data
Animal data
substances
In vitro data
Vulnerable group use (considered
with other factors)
Step Three, Part B: Critical Safety
Evaluation
The term, “other concerns,” as described in Chapter 3, encompasses concerns FDA becomes aware of without extensive information searching. These may include concerns expressed by other regulatory
agencies, concerns expressed in secondary literature, or concerns expressed by other organizations.
a
Low level evaluation: is there
evidence suggesting a concern
may exist?
Depth of evaluation
Level of information search Easily obtainable information (see
Table 4–1)
All ingredients are considered
“New” ingredients are
automatically flagged
Completed by
FDA
Factors and modifiers used Human data: serious adverse
events only
Other concerns, a as they come to
FDA's attention
Which ingredients
TABLE 3–1 Overall Framework
Step in the Process
42
FIGURE 3–1 Flowchart of Overall Framework
43
44
available data. However, this method is not transparent, could be biased, and the exact ranking of the
ingredients may tend to be somewhat arbitrary.
• Sales volume. On the basis (that an unsafe product would do the most harm if it reaches a large number
of people, ingredients could be sorted by sales volume and those with the highest sales volume sent first
through the screening/flagging and priority-setting steps. The major disadvantage of this system is that
sales volumes are not static and sales figures serve only as proxy estimates of use. Another problem
with this system is that as a class, vitamins will have the highest sales volume although their safety has
been more thoroughly monitored than other classes of dietary supplements. It might therefore be
appropriate to begin with the top sellers in the different classes of substances (e.g., the top 10 to 20
percent of hormones, of botanicals, of animal products, of vitamins, and so on).
• Randomly, in no particular order. The advantage of a random approach, rather than a systematic one, is
that initiation of the process will not require additional resources and time investment.
One of these methods, or a combination of them, may be an effective way for FDA to initiate the screening
process of ingredients described in this report.
Description of the Process
The first two steps in the process, screening/flagging and priority setting, are organized to categorize dietary
supplement ingredients based on concern and therefore immediacy of need for subsequent in-depth evaluation of
safety, the third step of the process. All three steps of this proposed framework are described in detail in
Chapter 5 and briefly below.
Information or Factors Used to Identify or Flag Ingredients for Further Evaluation
Several types of readily available information, or “factors,” are used to identify ingredients warranting
farther consideration, as outlined in Table 3–1 and Figure 3–1, and described in more detail in Chapters 4 and 5.
The first factor considered is the ingredient status; ingredients introduced to the market as dietary supplements
after 1994 are automatically flagged in Step One to be reviewed in Step Two, priority setting. For pre-1994
ingredients, evidence of serious adverse events in humans is considered. If there is evidence of serious adverse
events that may be related to a specific dietary supplement ingredient, that ingredient is flagged. The next
consideration is “other information” available to FDA. This other information factor encompasses a broad range
of potential concerns. Information that may make FDA aware of potential problems ranges from materials
prepared by other groups that have evaluated the safety of dietary supplements, to expressions of concern from
consumer protection or advocacy organizations. All flagged ingredients enter the priority-setting step of the
framework (Step Two).
Evaluation and Weighting of Available Information
In Step Two, the priority-setting step, several key types of information about each flagged ingredient are
considered. These types of information, or factors, are described in Chapter 4. They include human data, animal
data, bioactivity of related substances, and in vitro data.
45
Information about each of these primary factors is retrieved and four key aspects of these data are considered:
•
•
•
•
the relevance of the information to safe use by consumers;
the potential seriousness of the harm reported;
the methodological quality of the evidence; and
the quantity of the evidence.
These aspects are used to give each ingredient a score for each of the four factors. The information for each
factor in also considered in terms of how it might suggest possible susceptibility of particular subpopulations.
After the scores are tabulated, they are sorted into several priority groups based on the scores, the hierarchy of
the different types of data, and the estimated prevalence of use of the ingredient. This sorting process allows
FDA to consider the different factors independently and individually for each ingredient.
Monograph Preparation, Internal Review, and In-Depth Safety Evaluation
As high priority ingredients are identified, safety review monographs will be compiled (Step Three) as
described in Chapter 6. In this step, industry and other stakeholders are invited to bring forward information
relevant to the safety of the ingredients being reviewed. Monographs will then be drafted. Monographs will
include comprehensive reviews of human data, animal data, other different types of evidence about the
ingredients' safety, and notations of where information is lacking. The monograph preparation may be done by
FDA or may be contracted out. Once the monographs are prepared, FDA will decide whether to turn them over
to an external advisory committee for further attention, to take action without further input from an external
advisory committee, or to take no action at the current time. If FDA decides not to take immediate action, it
could choose to make the monographs available as draft monographs. FDA may later decide to take action or to
refer the ingredient to an external advisory committee, especially if additional information becomes available. A
decision not to take further action does not indicate that the product is safe, and FDA may choose not to make a
statement about the safety of the product.
If the data do not lead to a clear-cut FDA decision, then the ingredient and its draft monograph are referred
to an external advisory committee for analysis and advice, and the draft monograph is made public. The external
advisory committee will review the draft monograph, collect additional information as needed, and provide
opportunity for public input on the ingredient's inherent safety. The external advisory committee will review the
science base for the monograph and revise it as necessary. Finally, the committee will summarize the science
relevant to assessing safety of the ingredient and provide opinions on the possible risks associated with the
ingredient, including risks that may be specific to particularly vulnerable subpopulations. The committee will
also outline where additional research may help resolve safety questions. The revised monograph and the
committee's comments will be made available to the general public, so that the expert opinions of scientists are
known even if no action is taken.
46
Ongoing Review and Reassessment
As new information becomes available to FDA, re-evaluation of internal draft monographs and monographs
revised by an external advisory committee may be necessary. Such new information should be considered as
described in the priority-setting step to determine if there is sufficient substantive new information to review and
possibly revise the monograph.
REFERENCES
Betz JM, White KD, der Marderosian AH. 1995. Gas chromatographic determination of yohimbine in commercial yohimbe products. J
AOAC Int 78:1189–1194.
CFSAN (Center for Food Safety and Applied Nutrition). 2000. Dietary Supplement Strategy (Ten Year Plan). Online. Food and Drug
Administration. Available at http://vm.cfsan.fda.gov/~dms/ds-strat.html. Accessed March 5, 2002.
Chambliss WG. 2001. Nutraceutical formulations: Impact on bioavailability. In: Examining the Science Behind Nutraceuticals: Proceedings
of the AAPS Dietary Supplements Forum. Arlington, VA: AAPS Press. Pp. 367–380.
FDA (Food and Drug Administration). 1997. Current good manufacturing practice in manufacturing, packaging, or holding dietary
supplements; Proposed rule. Fed Regis 62:5699–5709.
Foreman J. 2000. St. John's wort: Less than meets the eye. Online. The Boston Globe. Available at http://www.boston.com/globe/search/
stories/health/health_sense/011000.htm. Accessed March 5, 2002.
GAO (General Accounting Office). 1997. Medical Device Reporting: Improvements Needed in FDA's System for Monitoring Problems with
Approved Devices. HEHS-97–21. Washington, DC: U.S. Government Printing Office.
Green GA, Catlin DH, Starcevic B. 2001. Analysis of over-the-counter dietary supplements. Clin J Sport Med 11:254–259.
Hamilton-Miller JM, Shah S, Winkler JT. 1999. Public health issues arising from microbiological and labeling quality of foods and
supplements containing probiotic microorganisms. Public Health Nutr 2:223–229.
Howe K. 2000. Herb Remedies: Panacea or Problem? Online. San Francisco Chronicle. Available at http://www.sfgate.com/cgibin/
article.cgi?file=/chronicle/archive/2000/06/02/MN75760.DTL. Accessed March 5, 2002.
Kamber M, Baume N, Saugy M, Rivier L. 2001. Nutritional supplements as a source for positive doping cases? Int J Sport Nutr Exer Metab
11:25 8–263.
Marrone CM. 1999. Safety issues with herbal products. Ann Pharmacother 33:1359–1362.
47
4
Factors Considered in Screening, Setting Priorities, and Safety
Evaluation
In any scientific evaluation there are different categories of data that are useful and that could be termed as
key factors to consider. It is helpful to collect and sort relevant information according to these categories. This
chapter describes the different types of scientific evidence and other information, herein termed “factors,”
thought to be most useful when screening, setting priorities, and conducting a critical safety evaluation of a
dietary supplement ingredient. Different factors contribute to each step of the framework process to a different
degree, and different sources of information are necessary to examine and evaluate the factors in the various
steps of the process.
DESCRIPTION AND USE OF KEY FACTORS
This chapter includes a description of each factor, limitations when considering the different types of
information grouped under the factor, and suggestions for how each factor is used in each step of the process. In
addition, the different sources of information for each factor are outlined in Table 4–1. These sources of
information may change over time and new sources may be added. It is likely that, with use, the systematic
approach described in this report will eventually evolve into an increasingly efficient and effective system as
experience and an accumulating database inform and organize the process.
Of the key factors described below (human data, animal data, biological activity of related substances, and
in vitro data), the primary factor that contributes to decision making at all steps of the framework is the evidence
of harm in humans. This is provided by data collected in observational studies and clinical trials, spontaneously
reported adverse events, and other sources of information about the consequences of use in humans. Whether or
not the ingredient is new, and thus safety cannot be ascertained as readily, is also considered in the screening/
flagging step. This is classified as the “new ingredient status” question.
In the descriptions below, each factor is defined, a rationale for its use provided, and limitations in the use
of these types of data are described. A general description of how each factor can be used at each step of the
process is then outlined, including a description of the appropriate information sources to consider at each step in
the process—ranging from easily obtainable information for the screening/flagging step to an increasingly
comprehensive information collection for the priority-setting and critical safety evaluation steps. Finally,
Consider under “Other Concerns”
Biological activity of structurally related or
taxonomically related substances
In vitro data
Animal data
Literature searches (e.g., IBIDS, MedLine,
Toxline, Embase)
Database searches (e.g., NAPRALERT,
Poisindex, Naurac)
Secondary reviews b
Poisonous plants (Kingsbury, 1964)
NAPRALERT
Literature searches (e.g., IBIDS, MedLine,
Toxline, Embase)
Database searches (e.g., NAPRALERT,
Poisindex, Naurac)
Secondary reviews
TABLE 4–1 Sources of Information for Key Factors and Modifiersa
Screening/Flagging
Priority Setting
Key Factors and Modifiers
Key factors
Human data
Serious adverse events:
Sources listed at left
MedWatch
Secondary reviews
Poison Control Center
Cursory search in scientific and medical
literature including IBIDS, Medline,
Toxline
Letters to the Center for Food Safety and
Applied Nutrition
Data voluntarily provided by industry
All available sources, including:
Published case reports—available through
MedLine or other literature
Unpublished safety information requested
from published clinical studies
Unpublished safety information requested
from manufacturers
Prepublication safety information requested
from clinical trials
Discovery materials from tort litigation
Data provided by animal poison control
centersc
Monograph/Critical Evaluation
48
Not applicable
Same sources as key factors Same sources as key factors
Not applicable
Not applicable
b
information sources are likely to change over time.
Secondary reviews include Commission E monographs, Agency for Healthcare Research and Quality evidence-based reports, American Herbal Products Association monographs, Natural Medicine
Comprehensive Database, World Health Organization monographs, Dietary Reference Intakes by the Institute of Medicine, and National Toxicology Program reviews.
c The Animal Poison Control Center of the American Society for the Prevention of Cruelty to Animals (ASPCA) will provide database information on its cases if requested by the Food and Drug
Administration (Personal communication, S. Hanson, ASPCA Animal Poison Control Center, May 17, 2002).
aThese
Industry estimates of production and sales (e.g., U.S. Consumer [2000])
Surveys describing supplement use
Large-scale, cross-sectional data collection (e.g., the National Health and Nutrition Examination
Survey, the Centers for Disease Control and Prevention, the U.S. Department of Agriculture, the
Continuing Survey of Food Intakes by Individuals, the Food and Drug Administration)
Vulnerable groups
Same sources as key factors (human data, animal data, structure/chemotaxonomy, in vitro)
New ingredient status 75-day advance notifications
Modifiers
Prevalence of use
49
50
overarching guiding principles are presented to explain the scientific basis for the suggested use of each
factor throughout the framework. These guiding principles will again be emphasized in the critical safety
evaluation process described in Chapter 6.
Key Factor: Data from Humans and Clinical Evidence of Harm
To identify possible concerns regarding safety, it is essential to examine data and information on undesired
effects that may have occurred in humans. These undesired effects are referred to as adverse events, a term that
does not imply that a particular substance caused the event, but simply indicates that the untoward effects
observed were associated with its use and might be related to the ingested substance (ICH, 1996). Information
about the occurrence of adverse events in humans is obviously the data most relevant to the supplement
ingredient in other humans. Information about adverse event occurrence in humans has its own limitations,
however, and must therefore be interpreted carefully. This section describes different sources of information
about data on adverse effects of dietary supplement ingredients in humans and considerations for using the
different types of available information.
When human data suggest risk, these are the most relevant data for consideration of human safety.
However, it is anticipated that applicable human data from experimental studies, observational studies,
spontaneous reports, and historical use sources often will not be available. As discussed below, the limitations in
using available human data often lead to its value only as a signal generator, but even weak data may be useful in
this capacity.
Information about untoward effects associated with the use of supplement ingredients may come from
experimental studies designed to examine the efficacy or safety of a substance, epidemiological studies, case
reports or series, spontaneous adverse event reports to the Food and Drug Administration (FDA) or to poison
control centers, or anecdotal reports in the history of the substance's use. Each of these sources provides a
different type of potentially valuable information.
Clinical Trials
It is helpful to first consider the ideal source of data and then consider limitations of other sources of data. If
available, the “gold standard” for determining the safety of an ingested substance is considered by many to be
the randomized, controlled clinical trial (RCT) that is designed to assess safety as well as efficacy.
The ideal RCT would enroll a sufficient number of subjects who are systematically monitored for a
sufficient amount of time to detect a wide array of adverse effects or physiological changes that might warrant
concern. It is the usual practice in an RCT to query subjects for possible adverse events at defined intervals and
to record and evaluate these events as “definitely,” “probably,” “possibly,” or “not” related to the ingested
substance (ICH, 1995). The use of randomization and control groups enables scientists to determine the
likelihood that adverse effects are actually due to the substance rather than to confounding factors. Limits to the
generalizability of the study include the statistical power of the study to detect adverse events, differences
between the study and target populations, and differences between how a substance is administered during the
RCT and its actual use by the general population.
Most RCTs are designed to assess beneficial effects. Thus, in general, efficacy results are more reliably
reported than safety data (Ioannidis and Lau, 2001). Although those conducting efficacy trials are expected to
observe and report adverse reactions, the extent and detail of this
51
reporting is highly variable (Ioannidis and Lau, 2001). In some cases, however, investigators may be able to
supply unpublished data useful in the safety evaluation, even if the published results do not contain all the
available information about adverse events (Ioannidis et al., 2002).
While investigators may be able to provide unpublished additional data, characteristics of the study design
itself may limit usefulness in predicting safety because even large studies may lack sufficient statistical power to
detect adverse events of low incidence. Adverse events generally occur at rates much lower than desired effects
(FDA, 1995). Clinical trials generally are designed to detect one primary endpoint, thus secondary events, such
as adverse effects, will typically be inadequately reported (Ioannidis and Lau, 2001). A major cause of an
incomplete safety evaluation is that the unexpected adverse events may not be noticed by the subject or detected
by the investigator if they fall outside the investigator protocol.
For these reasons, a study to test the effects of a supplement ingredient on mood, for example, may not
detect potentially dangerous cardiovascular effects if heart function is not monitored. Even if investigators are
alert for adverse effects, the limited number of subjects, the limited duration, and the unrepresentative nature of
populations studied limit the sensitivity in detecting adverse events that would occur infrequently, after extended
exposure, or in subpopulations. For example, events that occur at the rate of 1 in 1,000 would require a study
with at least 3,000 subjects at risk to have a 95 percent chance of being detected (Lewis, 1981).
Although RCTs can be limited in their sensitivity, they do provide valuable information when adverse
events are detected. Information from clinical studies is strengthened by the following information (Counsell,
1997; ICH, 1995; Moher et al., 2001):
•
•
•
•
•
•
demographic information on the study population;
inclusion and exclusion criteria to determine if the results are generalizable;
description of the condition or disease and comorbidities of the study population;
description of the intervention (supplement ingredient [composition], dose, and duration of exposure);
list of prior and concomitant ingested substances, including dietary supplements and drugs; and
description of the adverse event including temporal relationship to ingestion of supplement ingredient
(response to discontinuation or rechallenge).
Observational Epidemiological Research
As discussed above, a limitation inherent to many RCTs is that size and duration limit sensitivity to detect
adverse events (FDA, 1995). Latent or delayed effects that occur long after exposure may not be detected.
Information about these latent and infrequent effects often comes from observational or epidemiological studies
that retrospectively or prospectively examine the effects of ingested substances on large populations. Like RCTs,
the value of observational studies also depends on the endpoints examined. For example, if a study evaluates the
incidence of cancer, death, or liver damage but does not evaluate anemia, the study is unlikely to detect
interference with iron absorption.
For the endpoints examined, cohort studies using registries and other sources of information about large
populations are a valuable source of safety information about ingested substances such as pharmaceutical drugs.
These types of studies would likely be informative about the safety of particular dietary supplement ingredients,
but unfortunately there are few studies of
52
this type conducted on them. The type of information needed to conduct such studies is rarely available for
supplement ingredients because their use is not systematically tracked in a manner similar to use of prescription
drugs.
Non-Study Information: Spontaneously Reported Adverse Events
Adverse events that are spontaneously reported to FDA, poison control centers, or as case reports or case
series in the medical literature are also important sources of information. Generally, these voluntary spontaneous
reports are made by consumers, physicians, or pharmacists who notice an untoward effect following ingestion of
a substance. It is assumed that adverse effects most likely to be attributed to the ingested substance are unusual,
persistent, or severe, and occur shortly following ingestion. Thus, effects that are not noticeable enough to garner
attention are unlikely to be associated with the ingestion of the ingredient and thus unlikely to be reported to
FDA or another data-collecting entity. Given these limitations, it is not surprising that the total rate of
spontaneous adverse-event reporting is very low (OIG, 2001), and that even fewer reports are made to FDA
(Chyka and McCommon, 2000).
It has been estimated that adverse events spontaneously reported to FDA account for only 1 percent of
serious drug reactions that occur outside the parameters of clinical studies (Scott et al., 1987). It is unknown if
spontaneous adverse event reporting may be even less frequent with dietary supplements, because it is unknown
if consumers are less likely to associate dietary supplements with untoward effects than to associate drugs with
untoward effects.Unlike drugs, supplement manufacturers and distributors are not required to share with FDA
the adverse event reports they receive (CFSAN, 2001a; OIG, 2001). Nonetheless, MedWatch and other sources
of reported serious adverse effects will often be the first line of evidence that indicates a substance might warrant
a higher priority review. Even when reports are inadequately documented and causation difficult to assess, the
reports should serve as sentinel events that alert regulators and the medical community to potential adverse
effects of a product.
In summary, when they exist, spontaneous reports of adverse events and published case reports are useful
for generating hypotheses about relationships between supplement ingredients and untoward effects. However,
due to the nature of adverse event reporting, especially for dietary supplement ingredients, a lack of reports does
not imply that a dietary supplement ingredient is safe. Similarly, the existence of adverse event reports does not,
without extensive critical evaluation of the reports, establish a causal relationship between the adverse event and
the ingredient.
Non-Study Information: Historical Use
Experience from generations of use in humans is often referred to as evidence of safety for modern day
supplements that bear resemblance to substances used historically. Some botanicals, for example, have had a
long history of medicinal use in many cultures.
Historical use is of less importance when relevant clinical, epidemiological, or animal toxicity data exist.
For many supplements, however, the amount of scientific and experimental data that exists ranges from scant to
nil. Recognizing that a full range of data is unlikely to be available for many dietary supplement ingredients,
historical use may be taken into account as a limited surrogate measure for toxicity in the absence of relevant
scientific and experimental data. In doing so, it is important to consider the relevance of the traditional use to the
current use. Historical information is only useful if the product in question is not so far removed from
53
the original plant use as to constitute a distinct entity. For example, a whole root extract that was traditionally
used for three days to treat a cold is not comparable to a fraction of a leaf extract promoted for long-term use to
treat cancer. The discussion in this section focuses on questions to help assess how to consider the relevance of
information about traditional use. These questions are listed in Box 4–1 and are explained in more detail below.
BOX 4–1 QUESTIONS TO BE ANSWERED WHEN CONSIDERING RELEVANCE OF
INFORMATION ABOUT HISTORICAL USE
• Is the supplement ingredient one that was commonly used within the context of a traditional medical
system?
• If the supplement ingredient is a botanical, is the part of the plant marketed the same as the part that
was traditionally used?
• Is the preparation a crude preparation, extract, or concentrate; a selected fraction; an isolated
compound; or a mixture of these? How similar is the current preparation to that used traditionally?
• Are current intake levels or recommended intake levels clearly different from traditional use?
• Is the modern duration of use consistent with historical use?
• Is the modern indication consistent with historical use?
• If there are traditional cautions in the use of the supplement ingredient, are these cautions typically
heeded?
• Are there other reasons to expect a different toxicity profile for the modern formulation than for the
traditional preparations?
If the supplement ingredient is a botanical, is the part of the plant marketed the same as the part that was
traditionally used? Safety comparisons for botanicals can only be made when the same plant part used in
traditional preparations is used in the modern preparation. Seeds, roots, leaves, and other parts may have distinct
safety profiles due to different composition. For this reason, this report defines the specific plant part as the
ingredient under question. Indication of safe use of one plant part should not be used as prima facie evidence that
other plant parts might also be used safely.
Is the preparation a crude preparation, extract, or concentrate; a selected fraction; an isolated compound;
or a mixture of these? The method of preparation can have an impact on an ingredient's safety. This is most
clearly illustrated in botanicals with traditional medicinal uses. Traditionally, most orally ingested medicinal
herbs were administered as crude aqueous extractions of plant parts that were soaked, steeped, or boiled in water.
Today's supplements are often sold in a different form—as encapsulated dried herbs, fluid extracts, solid extracts
(such as capsules or tablets), or foodstuffs containing herbal extracts. While these modem formulations are not
equivalent to traditional preparations and may not have exactly the same effect as teas and infusions, they could
have safety profiles similar to traditional preparations. A botanical with a history of benign use in infusions may
or may not manifest new toxic effects when concentrated, lyophilized, or encapsulated. Teas (infusions) are
typically extracts prepared from dried plant materials, while lyophilized plants are made from whole fresh
materials. The chemical composition and concentrations could be sufficiently different between the two forms to
result in different safety profiles. Even if dried and lyophilized materials were identical in all respects, an
infusion of a botanical should not be thought of as necessarily comparable to whole
54
dried botanicals because the chemistry of the extract (tea) may be different. Differences in safety profiles could
also be expected for alcoholic extracts of plants with known toxic components. Alcohol draws out different
compounds, so alcohol extracts may contain a higher concentration of toxic compounds than aqueous extracts.
An example is wormwood (Artemisia absinthium), which in an aqueous extract contains little thujone (a
neurotoxin) (Tegtmeier and Harnischfeger, 1994), but may contain substantial amounts of thujone in alcohol
extracts. Additionally, isolated compounds may be dissimilar to traditional plant extracts in safety, as could
extracts to which isolated compounds (e.g., yohimbine, ephedrine, hypericin) have been added.
Are current intake levels or recommended intake levels clearly different from traditional use? A frequently
quoted axiom of toxicology from Paracelcus is that “dose makes the poison.” Unfortunately, differences in
traditional and modern formulations render dose comparisons difficult or even impossible. In the rare cases
where active compounds or groups of compounds are known and have been quantified (e.g., kavalactones in
kava [Piper methysticum], ephedrine alkaloids in Ephedra sinica), doses can be compared. In most cases,
however, dosing comparisons are so imprecise that it should probably only be attempted in cases where the
modern formulation is clearly providing doses that are orders of magnitude higher than traditional doses. For
example, consumption of a culinary herb in small amounts in cooked food may have different effects than
medicinal consumption of large amounts of the same herb, rendering a safety extrapolation from culinary to
supplemental use inappropriate.
Is the modern duration of use consistent with historical use? Is the modern indication consistent with
historical use? The duration of use is another component of dosage that should be considered. Acute, short-term,
and long-term intakes all have different safety implications. A lack of adverse events reported for an herb
traditionally used only for a few days has little relevance to safety of the same herb chronically ingested. When
considering how the current duration of use compares to traditional duration of use, it may be helpful to also
consider whether the modern day indication is consistent with traditional indications. The modern uses of some
botanicals, especially for nonmedical indications such as memory enhancement and ergogenics, for example,
might lead consumers to use supplements chronically that were never used chronically in traditional medicine.
If there are traditional cautions in the use of the supplement ingredient, are these cautions typically
heeded? Some dietary supplement ingredients, such as some botanicals, were traditionally prescribed by
practitioners knowledgeable about contraindications to their use. It is scientifically appropriate to take
contraindications in traditional use into account when considering the safety of the ingredient. If, for example, an
ingredient traditionally contraindicated for pregnant women is currently being marketed to pregnant women or
frequently consumed by pregnant women due to its expected effects, then FDA should be more concerned about
the safety of this ingredient.
In summary, it is clear from these questions that historical use, even widespread historical use, is no
guarantor of long-term safety. Historical use information is very useful when it describes a relationship between
untoward effects and an ingested substance. It is less useful in predicting harmful effects, especially those effects
that do not occur immediately following exposure. However, in the absence of scientific or experimental data,
historical use may provide indirect evidence for lack of serious acute harmful effects, and it may be useful to
compare with current cautions and exposures (intake levels and duration). Because little other data may be
55
available for many ingredients, it is important to judge the relevance of traditional use information to current use
conditions.
Causation in the Consideration of Adverse Events
For adverse events from any type of study or nonstudy source, ascertaining whether or not a causal
relationship exists between the adverse events and the ingestion of the ingredient is likely to be a challenging
aspect of considering human data. At the screening/flagging step of the process, ingredients should be flagged
without a burdensome evaluation of actual causation. At the priority-setting step to a limited degree, and in the
critical evaluation step to a much greater degree, the evidence should be evaluated for causation. Generally
accepted causation criteria for assessing the relationship between adverse events and drugs are outlined by
Sackett and colleagues (1991). These criteria, listed below, should generally be applicable to other ingested
substances as well, including dietary supplement ingredients.
•
•
•
•
•
•
The adverse effect is well accepted as an adverse reaction.
There is no good alternative candidate (unexplained exacerbation or recurrence of underlying illness).
The timing is as expected for an adverse reaction to this compound.
The blood level or other biomarker provides unequivocal evidence of overdose.
The adverse effect improves suitably if the individual is not rechallenged with the compound.
The adverse effect unequivocally recurs or is exacerbated on rechallenge.
These causation criteria and the quality and documentation of the data will be helpful in weighting the
information collected about adverse events reported, but it is not necessary for causation to be clearly
demonstrated or refuted during any step of the process.
The different types of human data discussed in the sections above are considered in all steps of the
framework, but the degree to which the data are evaluated varies significantly with each step. The differences are
summarized below and discussed further in Chapters 5 and 6.
Use of Human Data in the Screening/Flagging and Priority-Setting Steps
There are several primary differences in how human data are considered at each step. The first difference is
that in the screening/flagging step, the occurrence of serious adverse events, rather than all adverse events, is
used to flag ingredients that should be considered in the priority-setting step. This distinction is made because
including nonserious adverse events in the screening could serve to dilute the efforts with untoward
consequences that are nuisances or inconveniences (flatulence or halitosis, for example), but do not cause
morbidity or mortality. Serious adverse events are defined in the Guideline for Good Clinical Practice issued by
the International Committee on Harmonization (ICH, 1996) and endorsed by FDA (FDA, 2002). A serious
adverse event is an untoward effect that is a death, life-threatening event, initial or prolonged hospitalization,
disability, congenital anomaly, birth defect, or other important medical event (ICH, 1996). In contrast to the
screening/flagging step, serious and nonserious adverse events are considered in the priority-setting and critical
safety evaluation steps.
The second difference in how human data are considered at the screening/flagging and priority-setting steps
is the degree to which causation is considered. As described above, the
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term adverse event encompasses all untoward effects that may be associated with the supplement ingredient,
even if the ingredient has not been demonstrated to actually cause the effect. At the screening/flagging step, the
relationship of the adverse event and the ingredient (i.e., the causality) is considered to some degree, but it is
considered less at this step than in the priority-setting and critical safety evaluation steps when more information
and resources are available to examine causality. That is, ingredients are flagged in the screening/flagging step if
a causative relationship between the ingredient and the adverse event cannot easily be ruled out.
The level of information gathering at each step also varies. For the screening/flagging step, readily or easily
obtainable sources of information about serious adverse events should be explored. Data sources could include
MedWatch and the Poison Control Center database that collect adverse event reports from consumers,
pharmacists, physicians, and hospitals. A cursory search of the medical literature should also be conducted to
determine if there are any reports of serious adverse events associated with supplement ingredients.10
At the priority-setting step, FDA should invest additional effort into weighing the strength of the evidence
that a relationship exists between the supplement ingredient and the adverse event. Although the consideration of
causation at this stage is not comprehensive, the reviewer makes some judgments about the strength of the
evidence.
Historical use information may also be used in the screening/flagging and priority-setting steps. The
screening/flagging step is focused on responding to indicators of concern, rather than on considering information
that may suggest an ingredient is safe. To the degree that historical use information provides insight into possible
concerns or subpopulations that may be harmed by the ingredient, it would be considered in these two steps of
the process. As stated above, historical use information can be considered as a surrogate indicator that acute
serious toxic effects are unlikely when other, more relevant safety information is not available. During the
priority-setting step, it therefore may be appropriate for the reviewer to consider relevant historical use
information to determine if it provides insight into areas of concern; such consideration may influence the
priority score (see Chapter 5 for the proposed scoring system).
Use of Human Data in the Critical Safety Evaluation Step
The purpose of the critical safety evaluation step is to consider all of the available and relevant information
about possible effects of the ingredient on humans, and to consider these data in the context of other types of
data collected (e.g., animal or in vitro). Available information should be collected, which includes published case
reports available through the National Library of Medicine databases and other sources. Also, clinical
investigators may have adverse event information that was not published. This information should be solicited,
as well as adverse event information from federal agency-sponsored studies in progress and materials discovered
by plaintiff lawyers in tort litigation. Importantly, the manufacturers and distributors of ingredients that reach the
critical safety evaluation stage should also be asked to provide data voluntarily on adverse events reported to
them or other relevant evidence they have regarding safety evaluation.11
10 For example, the National Library of Medicine's PubMed, available at http://www.ncbi.nlm.nih.gov/entrez/query.fcgi;
TOXNET, available at http://toxnet.nlm.nih.gov/; and EMBASE, available at http://www.embase.com/.
11 Manufacturers and distributors are always welcome to submit adverse event reports and other safety information. They
are specifically requested to submit data after the priority-setting step because at this step additional effort can be expended to
request information about specific ingredients in the Federal Register and/or via letters to individual manufacturers and
distributors, if they are known.
57
In the critical safety evaluation step, experts will weigh the evidence and consider the likelihood that a
substance poses a risk to human health. At this point, consideration of human adverse event data in relation to
the other factors, such as animal, in vitro, and biological activity of related substances, will provide an overall
picture of what is known about the ingredient's safety and may provide plausible biological explanations for
reported human adverse events for which causation is not clear.
While it is hoped that eventually all dietary supplement ingredients will reach the critical safety evaluation
step, given the large number of dietary supplement ingredients, it is unlikely that those ingredients for which
significant safety concerns have not been raised will reach this step in the near future. Thus, ingredients that have
been safely used historically are unlikely to be reviewed unless other information leads to questions about their
safety.
Information about the historical use of an ingredient will be the most useful during the critical safety
evaluation step, when it can be considered along with the in-depth analysis of potential for harm derived from
other information. In this step, historical use information will be considered to the degree that the historical use is
similar to current use. The historical use information should not be considered as more important than the
scientific evidence, but it may be appropriate to take information about the history of use into account if it is
relevant to understanding the likelihood of the potential harm being considered and it is relevant to current use
conditions. For example, it would be important to determine whether the potential harm being considered would
be expected to have been detected during years of previous use. In such cases, historical use information may
mitigate concerns to some degree.
GUIDING PRINCIPLE FOR HUMAN DATA
A credible report of a serious adverse event in humans that is associated with use of a dietary
supplement ingredient raises concern about the ingredient's safety and requires further information
gathering and evaluation. A final judgment about the safety of the supplement ingredient, however,
will require consideration of the totality of the evidence. Historical use should not be used as prima
facie evidence that the ingredient does not cause harm. It may be appropriate, however, to give
considerable weight to a lack of adverse events in large, high-quality, randomized clinical trials or
retrospective or prospective cohort studies that are adequately powered and designed to detect
adverse effects.
Key Factor: Animal Data
Animal testing provides invaluable evidence about the potential for ingested substances to cause harm in
humans. Thus, studies on animals are regularly employed as an important step in attempting to predict untoward
effects of these substances on humans (see, for example, Redbook 2000 [CFSAN, 200 1b] or guidance
documents for new drugs [CDER, 2002). They are powerful because controlled studies can be conducted to
predict effects that might not be detectable with customary use by humans until they lead to harmful results.
Animal studies serve as important signal generators and, in some cases, may stand alone as indicators of
unreasonable risk.
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Different types of animal studies provide different types of information relevant to considering the safety of
a dietary supplement ingredient and can be classified as either traditional toxicology data or safety pharmacology
studies. FDA's Redbook II describes several different types of toxicology studies that are typically conducted in
assessing the safety of food additives and other ingested substances (see Table 4–2) (CFSAN, 1993). These
studies are applicable to evaluating most ingested substances, including dietary supplement ingredients,
irrespective of what is known about their biological activities. It is not anticipated that animal data of each type
will be available for each dietary supplement ingredient. However, consideration of the typical study protocols
enables the animal data that is available to be placed in perspective regarding the type of information gleaned
from the different study designs and the types of data that are often available for other ingested substances.
One type of animal study is the acute toxicity study.12 In acute (single dose) and subacute (repeated doses)
toxicity testing, animals are treated with increasing amounts of the test substance to determine the dose that
induces overt abnormalities (i.e., toxic effects). The resulting abnormalities might be at the level of organs
(detected by gross examination or by observing behavioral changes), cells (detected by histological examination
such as light or electron microscope analysis of fixed tissue samples), or subcellular structures (detected in
biochemical studies such as enzyme assays or protein analysis). In another example, chronic toxicity testing (and
in subchronic toxicity testing, which is not as lengthy as chronic toxicity testing), the test substance is typically
administered to animals on a daily basis for 3 to 24 months (depending on the species) to characterize possible
longer-term toxicity.
When conducting animal studies, blood levels of the test substance and its active metabolites are often
determined. These blood levels are used to provide evidence that the test substance was absorbed, to describe the
dose-response curve, and to determine whether the metabolites formed in the test animal are qualitatively and
quantitatively similar to those formed in humans. If the metabolites formed in the animals are not the same as
those formed in humans, the results may be less meaningful and testing with other species should be considered.
Genetic, reproductive, developmental, and behavioral toxicity studies, as well as other types of studies
provide further information regarding the toxicity of the test substance.
In addition to traditional animal toxicity testing, safety pharmacology testing is also conducted in various
animal species in order to detect alterations in physiological functions at doses lower than those used to elicit
overt toxic effects detected in animal toxicity testing. The S7A Safety Pharmacology Studies for Human
Pharmaceuticals issued by FDA defines safety pharmacology studies as “those studies that investigate the
potential undesirable pharmacodynamic effects of a substance on physiological functions in relation to exposure
in the therapeutic range and above” (ICH, 2001). Safety pharmacology testing generally focuses on endpoints
that differ from those examined in classic toxicity testing. It is designed to detect harmful effects in a “core
battery” of vital organ systems, which include the cardiovascular, central nervous, and respiratory systems.
Safety pharmacology studies may detect potentially harmful physiological responses such as arrhythmias,
blood pressure changes, and alterations in blood gases in nonrodent species—changes that would be difficult to
observe in rodent species. When appropriate, supplemental safety pharmacology studies beyond the core battery
is used to evaluate potential adverse effects in the renal/urinary, autonomic nervous, gastrointestinal, immune,
skeletal muscle, and endocrine systems.
12
See descriptions of acute, short-term, subchronic, one-year, and chronic toxicity tests in Table 4–2.
SOURCE: Center for Food Safety and Applied Nutrition (CFSAN, 1993, 200 1b).
Protocols Typically Used in Studies
Single dose (limit test, up to 5 g/kg body weight or 5 m1/
kg body weight) followed by 14-day observation period
Estimate acute lethality, if appropriate, for test substance
Monitor food consumption, weight change, lethargy,
changes in behavior
Short-Term Toxicity Tests
Daily dosing regimen is repeated for 14 or 28 days
Species used: usually rat but other species such as
At least three and up to five different doses are used
Observe general signs of toxicity: change in consumption
mouse, dog, or miniature swine may be used
of diet or water, change in body weight; hematology,
clinical chemistry and limited urinalysis (prestudy and at
termination); neurotoxicity and immunotoxicity studies, as
appropriate; gross necropsy findings and microscopic
findings
Subchronic Toxicity Tests
Daily dosing regimen is repeated for longer period,
Species used: usually rat, mouse, or dog
typically 90 days (up to 12 months, depending on species)
Observations: same as for short-term tests described above
One-Year Toxicity Tests (nonrodent)
Similar to subchronic studies extended to 12 months
At least three dose levels are used
Species used: usually dog
Observe general signs of toxicity: change in consumption
of diet or water, change in body weight; hematology,
clinical chemistry, and urinalysis (prestudy, at 3-month
intervals, and at termination); gross necropsy and
microscopic findings
Observe specific signs of toxicity, if appropriate
Chronic Toxicity Tests (rodent)
Similar to subchronic studies extended up to 24 months,
Species used: two rodents, usually rat and mouse
depending on species
At least 25 female and male surviving to the end of the At least three dose levels are used; the high dose should be
study
the maximum tolerated dose (MTD)
Observe general signs of toxicity, as described above
Observe specific signs of toxicity, if appropriate
TABLE 4–2 Toxicity Studies in Laboratory Animals
Types of Studies
Acute Toxicity Tests
Species used: typically rat
Characterize possible long-term toxicity of the test
substance in rodents
Determine whether test substance is toxic when
administered to rodents in regularly repeated oral doses
for the major portion of the lifetime of the test animal
Identify target organs
Refine dose range for further studies
Establish NOAEL for additional endpoints
Characterize possible toxicity of the test substance in a
nonrodent species
Establish NOAEL in a nonrodent species
Identify target organs
Refine dose range for further studies
Establish the no-observed-adverse-effect level
(NOAEL) for some endpoints
Purpose of Study/Information Gleaned
Main focus: observe the symptoms and recovery of test
animals
Identify possible target organs
Estimate dose range for other studies
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60
In addition to information provided by laboratory animal studies, veterinary toxicology information may
also prove useful in examining the potential effect of an ingredient on humans. Information is available on the
effects of veterinary intoxication, similar to human adverse event reports. Serious adverse events reported in
animals, such as livestock, may provide helpful information. For example, effects associated with ingestion of
several plants were reported in livestock many years ago. Animal poison control centers, as well as a search of
the veterinary literature, may provide this type of information.
Importance of Quality Data
While all animal experiments may be informative, the nature of the experimental design, the quality of the
methodology, and the statistical significance of the results need to be taken into consideration in weighting the
evidence. Recommendations for well-designed safety tests using animals are described in the FDA Redbook
(CFSAN, 1993, 2001b). Specifically, the most ideal information will come from animal studies that are
consistent with the guidelines listed in Box 4–2, recognizing that other data may be valuable as well.
Extrapolations from Animal Studies
Several considerations are important when extrapolating from animal data to predict effects on humans.
Factors that can affect interpretation include interspecies physiological variability and differences in routes of
exposure, dose levels, animal health, nutrition, and treatment. Testing substances in more than one species
increases the likelihood that information related to effects in humans will be identified, and the more genetically
diverse the examined species (e.g., one rodent and one nonrodent study), the more likely at least one of these will
model human physiology.
The relevance of animal studies to human safety is also improved when treatment of the animal most
closely resembles conditions experienced by humans and does not result in excessive stress. A healthy, inbred
animal species is most likely to result in data that are
BOX 4–2 CHARACTERISTICS OF GOOD ANIMAL STUDIES
A good animal study is one that:
• uses Good Laboratory Practices;
• is specifically designed as a toxicity, safety pharmacology, or safety study and includes sufficiently large
doses to detect toxicity;
• uses unanesthetized, unrestrained animals on a semipurified diet;
• fully characterizes the composition and formulation of the test substance;
• uses a species that has pharmacodynamics similar to humans (bioavailability, distribution, metabolism,
excretion);
• estimates blood or other tissue levels to assure absorption;
• conducts clinical chemistry, blood, and urine analysis;
• uses more than a single species (that might respond differently than humans); and
• administers the test substance orally.
61
reproducible and reliable. Accreditation of laboratory facilities provides reasonable assurance that the animals
are being treated according to established guidelines (ILAR, 1996).
In considering animal data generated in other countries, it is important to recognize that animal care
accreditation is not globally harmonized. Animal data derived from studies in nonaccredited laboratories that do
not follow good laboratory practices may be difficult to interpret or reproduce, possibly because animals are
housed under stressful conditions, fed nonstandard diets, or have parasites or diseases that may confound the data
interpretation.
Finally, the amount administered and tissue levels of a substance in test animals are important to consider
when assessing the relevance of animal studies to human safety. One of the unique and powerful approaches of
animal testing is the system of administering high amounts of a substance over a short time period. This allows
the prediction of possible effects following prolonged human exposure and prediction of possible effects on
particularly sensitive subpopulations. Many studies focused on toxicity will evaluate increasing doses until signs
of toxicity are seen. While the amount administered may not appear relevant at first glance, organ toxicities at
elevated intake levels in acute or subchronic studies can be indicative of toxicities that may develop at lower
doses during chronic use of the ingredient.
Studies carried out using very different amounts or formulations from those being marketed must be
carefully interpreted. High-dose effects can be useful in predicting potential for similar low-dose effects in
humans, but these studies serve as indicators of risk or concern that should be considered in the context of other
data when possible. Finally, animals that are given substances using intragastric or oral administration provide
the ideal model to predict human toxicity or harm associated with a dietary component, but data following
administration by other routes should not be disregarded.
As with any type of scientific study, it is important to remember that a lack of observed or reported
detrimental effects in an animal study does not indicate that a particular substance is safe. Animal data should
only be used to predict human effects that are relevant to the endpoints examined in the animals. For example, if
an animal study only reported how many animals died or exhibited gross toxic effects following short-term
administration of an ingredient, it is not acceptable to conclude that this ingredient does not cause cancer
following chronic intake by humans. In summary, the sensitivity of the animal experiments to detect particular
effects is of utmost importance to consider when extrapolating from animal studies to humans.
Use of Animal Data in the Screening/Flagging Step
In order to create a rapid review system and to avoid lengthy data searches during the screening/flagging
step, animal and other nonclinical data are not designated as a separate, independent factor for this step. These
data are considered in this step to the extent that they come to FDA's attention under the umbrella of “other
concerns,” that is, without overt information-seeking action on the part of FDA.
Use of Animal Data in the Priority-Setting Step
The goal in considering animal data at this step is to set a higher priority on flagged ingredients for which
animal data suggest there may be safety concerns. In this step, the scientific literature should be systematically
searched for evidence of harmful effects in animals for all flagged ingredients (including ingredients flagged for
other reasons). Sources for primary scientific literature include IBIDS, MedLine, Toxline, AGRICOLA, and
other scientific
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literature databases. Other databases, such as NAPRALERT, focus on natural products and also may be useful
for searching for evidence of adverse effects observed in animal studies. Finally, it is important to consult several
secondary or tertiary reviews that may cite older (pre-1960s) or foreign data not found in the main database.
After gathering information, the evaluation of animal data should be focused on two aspects: the evidence
of possible risk, of which the quality and quantity of the data are components, and the seriousness of the
potential harm suggested by the data. Points to consider when assessing the quality of the data are outlined
above. The data are more meaningful when the dose and ingested form can appropriately be extrapolated from
animal data to human effects, as outlined above.
In addition to assessing the evidence of possible risk, it is very important to consider the seriousness of
effects suggested by the animal studies. Clearly, animal studies that predict serious harm or death warrant more
attention than those that predict mild, self-limiting effects on humans. Certain chronic animal toxicity or
biological activity data should be considered as immediate cause for high priority, regardless of the presence of
high-quality human data suggesting no acute toxicity. This is because human exposure may need to be prolonged
before such toxicities would be detected without the benefit of animal data, or the source of such detrimental
effects may very difficult to detect except with animal studies. Animal studies that warrant special concern are
those that indicate the following potential effects in humans:
•
•
•
•
•
evidence of cancer;
reproductive system effects;
developmental toxicity effects, including teratology;
acute organ toxicities; and
cardiovascular, respiratory, and central nervous system effects.
Use of Animal Data in the Critical Safety Evaluation Step
The goal of the critical safety evaluation step is to conduct an in-depth consideration of the value of the
available animal data in predicting harm to humans in the context of data from other factors. If animal data are a
central focus of the in-depth safety evaluation, expert opinion in the interpretation of animal data will be sought.
Such expert opinion will help ensure that the data are appropriately reviewed in the context of all information
available regarding the ingredient.
Industry and the other public communities should be invited to submit animal study information for
ingredients that reach the critical safety evaluation stage. If manufacturers or distributors have conducted animal
studies on their products, these data should be made available on a voluntary basis by manufacturers at this stage,
if not before. Veterinary toxicology information may also provide useful information; cases reported to the
animal poison control centers should also be solicited.
GUIDING PRINCIPLE FOR ANIMAL DATA
Even in the absence of human adverse events, evidence of harm from laboratory animal
studies can be indicative of potential harm to humans. This indication may assume greater
importance if the route of exposure is similar (e.g., oral), the formulation is similar, and more than
one species shows the same toxicity.
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Key Factor: Bioactivity of Structurally Related and Taxonomically Related Substances
Complete information on safety-related effects of each dietary supplement ingredient will not be available.
Consideration of risk may therefore be facilitated by understanding the biological activity of related substances.
It is not possible to define all the different ways that substances may be “related.” Substances with similar
chemical structures, such as ephedrine and amphetamine, are structurally related, as are substances that stimulate
or inhibit activity at the same cellular receptors or other biological targets, even if their chemical structures are
not obviously similar in the strictest sense. Similarity of dietary supplement ingredients to biologically active
metabolic intermediates such as cytokines or hormones may also be important if the actions of metabolic
intermediates provide clues about the activity of the dietary supplement ingredients. Finally, it is possible to gain
insight into the activity of a plant-derived substance by considering the activity of other plants in the same plant
family or genus.
For some dietary supplement ingredients, reviewing the biological activity of individual chemical
components or related chemicals will be straightforward and will lead easily to hypotheses about the action of
the dietary supplement ingredient being considered. If the biological activity of related substances suggests
concern that the dietary supplement ingredient may be harmful, these concerns should be considered.
In other cases it may be more difficult to identify substances related to the dietary supplement ingredient
that could be used to predict biological activities. In these cases, if an ingredient's chemical components are
known, it may be useful to employ systematic computational approaches to formulate hypotheses about
biological activities of the chemical constituents, as described below. In the case of botanical ingredients, it is
appropriate to review information about the individual chemical components to determine if any of the
constituents raise concerns and to review information about taxonomically related plants. These approaches are
described in the next few paragraphs.
Systematically Considering Biological Activity of Structurally Related Substances
The physical-chemical properties and biological effects of a substance are derived from its chemical
structure. If the chemical structure of a dietary supplement is known, but additional insight into the biological
activity is needed, then it may be helpful to consider the information about the biological activity of structurally
related substances. It is assumed that the biological effects of chemicals, including toxic effects, are implicit in
their molecular structures. On this basis, computational programs have been developed to predict the biological
activity of chemicals by comparing their chemical structures with other well-characterized compounds.
Computer programs designed to assist in predictive toxicology are useful in predicting a chemical's
potential propensity for causing particular effects. For example, The Open Practical Knowledge Acquisition
Toolkit program (AIAI, 2002) uses chemical structures and a variety of models to estimate carcinogenicity and
teratogenicity, among other toxicological endpoints, and is used by the Cosmetic Industry Review in setting
priorities for review. An endorsement or comparative evaluation of individual programs is beyond the scope of
this report, but these programs in general are believed to have value in providing insight into the potential for a
dietary supplement ingredient to demonstrate toxicological outcomes not adequately addressed by available
experimental data. Computational prediction is most useful for predicting biological activities of pure compounds.
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Considering the Chemical Composition of Botanical Ingredients
As discussed in Chapter 3, for the purposes of this framework, a plant part (e.g., fruit, root) is considered as
one dietary supplement ingredient, but of course this one ingredient is composed of many individual
phytochemicals. It is well known that biological effects are tied to specific pharmacophores, or chemical
structures, and that certain chemical structures are known to trigger a toxicological response. For this reason, it is
helpful in predicting the toxicity of botanical ingredients to know if they contain such compounds. Thus,
documentation of the chemical constituents known to be present in a botanical ingredient may enable safety
predictions to be made based the presence of compounds known to be hazardous. For example, the presence of
certain compounds, such as those listed in Box 4–3, can often point to a potential toxicity of a specific botanical
product.
In addition to examining chemical composition profiles of botanical ingredients for the presence of
chemicals associated with harm, much information can also be gained by reviewing what is known about plants
that are taxonomically related to the dietary supplement ingredient under consideration. A number of genera of
plants are often associated with toxic compounds (e.g., Liliaceae are known to contain cardiac glycosides,
Euphorbiaceae are known to contain phorbol esters and toxic diterpenes). The ability to anticipate the presence
of specific classes of compounds based on plant family or genus may be helpful in predicting potential toxicity.
For example, if the botanical belongs to a genus known to contain certain compounds for which there is a toxic
potential, one could presume that the same compounds might exist and pose a problem in the ingredient under
question, unless there is reason to think otherwise.
The utilization of taxonomic relationships to predict composition and potential toxicity has its limitations.
Not all genera of a given family will contain similar toxic components. Therefore, knowledge of taxonomy,
phytochemistry, and pharmacognosy is ideally used as a tool to complement other data such as bioavailability,
pharmacokinetics, and toxicological evaluation. Furthermore, the concentration of these compounds in the final
product must be considered, as well as the plant part being utilized and the manner of preparation, processing,
and formulation. The goal is to consider two likely scenarios that could provide some guidance regarding the
possible toxicity a botanical dietary supplement ingredient: where a known constituent of the plant is structurally
similar to a known toxic compound, and where a plant genus or species is (or is closely) related to a known toxic
plant.
BOX 4–3 EXAMPLES OF POTENTIALLY HAZARDOUS COMPOUNDS
•
•
•
•
•
•
•
•
•
alkaloids (usually active on the central nervous system as well as other organs or systems of the body)
cardenolides/bufadienolides (usually cardiotoxic)
colchicine-like compounds (toxic at very low doses)
cyanide-containing compounds
nitrophenathrenes (aristolochic acid, mutagens, carcinogens)
nitrosamines (carcinogens)
phorbol esters (irritants, tumor promoters)
pyrrolizidines (liver toxins, carcinogens)
urushiol-related compounds (poison ivy-type compounds, severe irritants)
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Use of Bioactivity of Related Substances in the Screening/Flagging Step
Consideration of the bioactivity of related substances is not a separate, independent factor of the initial
screening/flagging step. It is expected that ingredients that cause concern based on their structural or taxonomic
similarity to harmful compounds or plants will come to FDA's attention through secondary reviews highlighting
the potential for safety problems or through other mechanisms of expressed public concern.
Use of Bioactivity of Related Substances in the Priority-Setting Step
Information about the biological activity of related substances may be utilized as a predictor of possible
harm, and therefore a reason for considering a supplement ingredient as higher priority. In gathering information
for the priority-setting process, sources such as databases (e.g., the American Chemical Society's Chemical
Abstracts Service) and texts with information about biological activities of phytochemicals and plants will be
useful in examining whether the ingredient's chemical structure or plant's genus and species indicates a potential
for harm. Computational approaches that predict possible toxicological endpoints based on chemical structure
may be used for dietary supplement ingredients with identified major chemical components.
When considering the potential for botanically-based supplement ingredients to cause concern, several key
sources of information should be consulted in the priority-setting stage. Texts that list poisonous plants by plant
family, genus, and species are helpful in identifying harmful ingredients. Poisonous Plants of the United States
and Canada (Kingsbury, 1964) is a good example that lists examples of harmful plants and also contains
information helpful in identifying related plants. Databases (e.g., NAPRALERT) provide pharmacological and
toxicological information about plant compounds that is helpful in identifying potential toxic substances by the
taxa of botanicals.
Use of Bioactivity of Related Substances in the Critical Safety Evaluation Step
In the critical safety evaluation, information derived from comparison to the biological activity of related
substances should be considered as part of the totality of the evidence. For example, if the information suggests a
plausible mechanism of harm and could explain the human adverse events reported, then it may be appropriate to
find that the ingredient is not safe. If structure and taxonomic prediction data are a central focus of the critical
safety evaluation, expert opinion in the interpretation of such information will be sought. Such expert opinion
will help ensure that the data are appropriately reviewed in the context of all information available about the
supplement ingredient.
GUIDING PRINCIPLE FOR STRUCTURALLY RELATED AND TAXONOMICALLY RELATED
SUBSTANCES
The presence of a constituent that is structurally similar to known toxic or potentially harmful
compounds or a plant that is taxonomically related to known toxic plants suggests increased risk,
and therefore higher priority, unless there is evidence that the compound is not toxic or harmful,
the compound is present in concentrations that will not lead to harm, or there is other evidence
supporting the safety of the ingredient.
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Key Factor: In Vitro Data
In vitro studies are defined here as studies not conducted in humans or other whole animals. A wide range
of in vitro experimental systems are used to gain insight into the risk of adverse clinical effects of compounds.
These systems include isolated cells, microorganisms, subcellular components, and isolated organs. In vitro
assays often focus on measuring effects on cells and subcellular targets such as enzymes, receptors, and DNA.
The primary advantage of conducting in vitro studies is that their reductionist approach allows insight into a
compound's mechanisms of action that might be more difficult to obtain in a whole animal study, making in vitro
studies useful screening tools. They are also generally more rapid and less expensive, leading to a greater amount
of this type of data being available in the literature.
As mentioned above, it is the reductionist approach of in vitro studies that makes them powerful and
inexpensive assays useful for learning about effects and mechanisms of actions of compounds. The reductionist
approach of in vitro assays, however, requires that reviewers of these studies carefully consider their limitations
and caveats. It is very important, for example, to consider whether the compound applied to the in vitro system is
similar in identity and concentration to the compound that reaches the target (e.g., tissue, receptor, subcellular
component) in the human. After a substance is ingested, the metabolic fate of the compound and the amount of
the biologically active compound that actually reaches the target site is dependent on a multitude of processes
including absorption, distribution within the body, metabolism by liver and intestinal enzymes, and rate of
excretion. Knowledge of an ingredient's pharmacokinetics and in vivo metabolism will allow the most
appropriate interpretation of the relevancy of the dose used in the in vitro tests.
Botanical extracts provide an example of how important it is to consider bioavailability of the ingested
substances. When applied to cells in vitro, these extracts often contain polyphenolic compounds (e.g., tannins
and related compounds) that may reversibly or irreversibly bind to subcellular components such as enzymes,
signal transduction factors, and receptors where they cause effects. In a human, however, these compounds can
bind to the food bolus or be metabolized by gastrointestinal enzymes, becoming unavailable for absorption, and
therefore not exert the same effects on receptors and enzymes (Bravo, 1998; Yang et al., 2001). Another example
of problematic interpretation can be in hepatocyte cultures that do not always support expression of metabolizing
enzymes, causing some data to be misleading. In contrast, some cell cultures are established specifically to
evaluate metabolism of substances and can provide useful information. All cell types do not respond similarly to
a single substance, even when the cells originate from the same organ; one cell type may exclude or excrete a
compound whereas another cell will not, and another may behave differently due to its unique biochemical
pathways.
In the drug development world, results from some in vitro assays are considered predictive enough of
toxicological problems that the assays are used to screen compounds in development and influence decisions
about further development. For example, assays have been developed to identify compounds that may contribute
to the development of torsades depointes cardiac arrhythmia by slowing cardiac repolarization. Drugs that may
potentially contribute to this condition can be identified by in vitro experiments conducted with isolated organs
and measurement of potassium channel activity in isolated cells (Liu et al., 1998; Wang et al., 1998; Zabel and
Franz, 2000).
It is also possible to use in vitro assays to anticipate which dietary supplement ingredients may contribute to
supplement-drug interactions by studying the effects of a dietary supplement
67
ingredient on cytochrome P450 enzymes, which are important in the liver metabolism of drugs and supplements
(Budzinski et al., 2000; Obach, 2000; Piscitelli et al., 2000). In vitro assays that assess enzymes, receptors,
tissues, or other biological endpoints that might provide useful information in the context of other data are listed
in Box 4–4. As additional in vitro assays are developed and validated, they will be useful in identifying which
dietary supplement ingredient may potentially be associated with risk.
BOX 4–4 USEFUL IN VITRO ASSAYS
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
apoptosis induction
ATP synthesis inhibition
cell cycle effects
cell proliferation effects
cell transformation effects
cholinergic effects
cholinesterase inhibition or induction
cytolytic effects
cytotoxic effects
detoxification enzyme inhibition or induction
DNA damage
Epstein-Barr virus activation
histaminergic effects
hormone receptor binding studies
immunosuppressant effects
mitochondrial respiration inhibition
mitogenic effects
parasympatholytic and parasympathomimetic effects
pharmacokinetic alterations
phototoxicity effects
prooxidation effects
sympatholytic/sympathomimetic effects
Because of the difficulties that often exist in their interpretation, it is often appropriate to use in vitro data as
hypothesis generators or potential indicators of harmful health effects rather than as stand-alone demonstrated
indicators that in themselves suggest possible risk. However, some in vitro assays, when carefully conducted and
interpreted, provide valuable information beyond simply reinforcing observations from other systems or
generating hypotheses. When the relationship between the results of an in vitro assay and actual clinical or
animal outcomes has been demonstrated, thus validating the predictive value of the assay, then the in vitro assay
warrants careful attention.
Use of In Vitro Data in the Screening/Flagging Step
In vitro data are not a separate, independent factor of the initial screening/flagging step. It is expected that in
vitro data that raise concerns about the safety of a supplement ingredient will come to FDA's attention through
secondary reviews or other outlets for expression of public concern.
Use of In Vitro Data in the Priority Setting Process
Information about in vitro effects can be obtained from many of the same sources used to locate animal
data. These sources include literature databases and secondary and tertiary reviews. As with the other factors, at
this step it is important to consider what the in vitro data suggest about the risk and seriousness of possible harm.
68
Use of In Vitro Data in the Critical Evaluation Step
The same information sources used for the priority-setting step should be searched in greater depth for the
critical safety evaluation. In addition, industry and other public communities should specifically be queried for
any in vitro data on the safety of the ingredient being evaluated.
As discussed above, some in vitro effects in themselves raise substantial concerns about potential for harm.
These effects, as well as other in vitro assays with less clinical validation and independent predictive value,
become very important in assessing biological plausibility of observations made or predicted by other systems,
such as animal, human, or structural association. While it is not necessary to determine a rational mechanism of
harm to determine that an ingredient is potentially unsafe, it is valuable to identify possible mechanisms that
explain the totality of the data. In vitro studies can be very useful and irreplaceable in this regard. If in vitro data
are a central focus of the critical safety evaluation, expert opinion in the extrapolation of in vitro data will be
sought. Such expert opinion will help ensure that the data are appropriately reviewed in the context of all
information available regarding the ingredient.
GUIDING PRINCIPLE FOR IN VITRO DATA
In vitro studies can serve as signals of potential harmful effects in humans, but not as
independent indicators of risk unless an ingredient causes an effect that has been associated with
harmful effects in animals or humans and there is evidence that the ingredient or its metabolites are
present at physiological sites where they could cause harm. Alone, in vitro data should serve only
as hypotheses generators and as indicators of possible mechanisms of harm when the totality of
the data from the different factors is considered.
MODIFYING FACTORS
In addition to the key factors that explicitly contribute to the screening/flagging and priority-setting steps,
prevalence of use and vulnerability of subpopulations are considered as modifying factors. These two factors
must be considered when evaluating the different types of scientific evidence. Both are considered to some
extent in the screening/flagging step and when setting priorities for evaluation. Prevalence of use in the general
population, however, is not a factor considered during the critical safety evaluation.
Prevalence of Use in the Population
The number of individuals who could be at risk of harm due to overall use of the dietary ingredient in the
United States (or “prevalence of use”) can be estimated from various types of data that provide estimates of the
relative popularity of different ingredients. Across the wide variety of dietary supplement ingredients that are
currently available, there is a wide range of usage patterns in the population. Some ingredients are used only
rarely or by a small fraction of the population, while others are used by a considerable fraction. Dietary
supplements that are readily available or are consumed or marketed for common concerns and conditions are
more likely to result in a high level of usage, while those that are less widely available, used only
69
rarely, or used by few consumers would be expected to result in a low level of exposure on a population basis.
Estimating prevalence of use allows a qualitative consideration of population exposure and therefore how
much of the population may be at risk if an ingredient is harmful—a factor that is important in optimizing the
impact of a rigorous safety evaluation on public health. That is, from a public health perspective, it is more
logical to first allocate resources to evaluation of potentially harmful ingredients that have the potential to harm
many people before evaluating those ingredients that may only affect a small fraction of the population
(assuming other information is equivalent).
Relative consumption and prevalence of use of various dietary supplement ingredients in the general
population can be estimated from two types of data. One type is industry estimates of production or sales.
Dietary supplement industry publications such as the Nutrition Business Journal provide such data. Additionally,
manufacturers and distributors collect production data, unit sales data, and total sales information in dollars as a
normal component of business operations. The industry may be willing to make this information available.
Neither unit sales nor total sales data are ideal, but both can serve as proxy indicators useful in developing a
qualitative understanding about prevalence of use. Unit sales data, especially, allow a rough comparison of
relative potential use among different ingredients, serving as a surrogate marker of actual use of each ingredient
—information that is usually not readily available. One limitation with the use of sales figures, however, is that
these numbers are often collected and collated by methods that make cross-category comparisons difficult. This
is important to keep in mind when estimating relative ingredient use.
The second type of data about prevalence of use is that collected in surveys about supplement use.
Increasingly, national surveys that have traditionally collected information from a large number of persons
regarding health issues and conventional food consumption information are also collecting valuable information
about specific supplement use. An example is the expanded monitoring efforts of the National Health and
Nutrition Examination Survey. Although it may be several years before this information is available, the
expanded data collection will provide more detailed and useful information than is currently available.
Such surveys can provide data on prevalence of use in the general population as well as in specific
population groups. Most surveys also ask subjects about patterns of use and other information that is helpful in
estimating the effect of potential adverse effects on a population. Although some publications based on such
surveys group supplement ingredients into broad categories (e.g., vitamins, botanicals) for the purpose of data
analysis, other sources of information are likely to list specific ingredients or products. Even when data on
specific ingredients are not included in the published articles, such data might have been collected and might be
available from the investigators upon request.
One deficiency of older survey data sets is that frequency of use information was rarely collected (i.e.,
differentiating supplement use for only short intermittent periods versus chronic use). This type of information is
important because it augments the evaluation of total sales figures. Some ingredients that are widely sold may be
used less frequently than others. Whether a substance is used for short periods of time or chronically is
particularly important in evaluation of safety, because a product or ingredient that is used intermittently will
usually pose a smaller or different type of risk than one used chronically.
Another limitation of available information is in the collection and interpretation of data on combination
products or ingredients that are typically used in combination products (in addition
70
to formulation and sales as a single-ingredient product). Obtaining reasonably accurate estimates of usage of
ingredients that are largely consumed as components of combination products may be more difficult but may be
available from manufacturers of raw ingredients or if registration procedures for dietary supplement ingredients,
similar to that currently required for drugs, is implemented at some point in the future.
Prevalence of Use as a Modifying Factor in the Screening/Flagging Step
Information about prevalence of use is not considered as a key factor, but it is used as a modifying factor for
human data. Prevalence of use is considered in the screening of human data in that it may mitigate or exacerbate
concern. That is, if an ingredient is widely used but few adverse events are spontaneously reported, it is less
likely to be flagged than a rarely used ingredient with a similar number of spontaneously reported adverse events.
Prevalence of Use as a Modifying Factor in the Priority-Setting Step
The prevalence of use is considered in the priority-setting step only in establishing relative rank within a
Priority Group. Within each Priority Group (explained in Chapter 5), items that are widely used are moved to the
top of that Priority Group.
Prevalence of Use as a Modifying Factor in the Critical Evaluation Step
Prevalence of use is not considered in the critical safety evaluation step.
GUIDING PRINCIPLE FOR PREVALENCE OF USE DATA
Ingredients that are widely used by the general population should be given higher priority for
critical safety evaluation than less widely used ingredients with similar degrees of safety concerns.
This is consistent with the public health goal of producing the most impact from limited resources.
Use by Vulnerable Subpopulations
When considering the safety of supplement ingredients or other substances, it is important to consider that
some individuals may be particularly vulnerable to adverse effects from certain supplement ingredients.
Vulnerable subpopulations can be defined as groups of individuals who are more likely to experience an adverse
event related to the use of a particular dietary supplement ingredient, or individuals in whom such events are
more likely to be serious in comparison with the general population. Characteristics that contribute to such
vulnerability may be physiological, disease-related, or due to other aspects, such as therapeutic interventions that
are commonly utilized by the subgroup.
An example of a physiological characteristic that results in an individual's increased susceptibility compared
to the general population is the change in the capacity for metabolism of various dietary supplement ingredients
across the lifespan. Changes in metabolism may lead to variable concentrations of active compounds at sites of
action and result in different responses.
71
For example, elderly individuals are a potential vulnerable subpopulation for some ingredients in that aging is
associated with changes in the ability to digest, metabolize, or excrete some ingested substances (Munro, 1989;
Rosenberg et al., 1989). Supplement ingredients that are normally cleared by, or altered by, the kidney or liver
may potentially pose a greater risk to this subgroup than to a younger population. This factor should be
considered for supplements specifically directed toward an older population. Children also metabolize some
chemical substances differently than do adults, which for certain supplement ingredients might make children
more susceptible to adverse effects and should be taken into consideration for any supplements marketed toward
children. Likewise, differences in metabolism between children and adults may make children more resistant to
adverse effects of certain substances (Guzelian et al., 1992). Infants have limited hepatic function that may make
them particularly susceptible to certain hepatotoxic substances. Other age-related changes may involve receptors
or kinetic parameters such as the volume of distribution. Physiological changes that occur during pregnancy may
also influence susceptibility to adverse effects associated with particular supplement ingredients.
In addition to life stages that may alter responses to ingested substances, the presence of disease may also
result in enhanced susceptibility to adverse effects from particular ingredients. For example, hepatitis or renal
disease can significantly alter xenobiotic clearance, allowing compounds that are normally cleared rapidly to
accumulate to toxic levels. People who are prescribed critical medications to be used on a chronic basis may be
at greater risk of harm from drug interactions with various supplement ingredients. For example, people living
with HIV/AIDS or other chronic diseases may be taking drug combinations that may interact with supplement
ingredients, such as St. John's Wort, that alter cytochrome P450 activity (Ernst, 1999; Piscitelli et al., 2000).
Interactions between drugs and dietary supplements may be of particular concern when both are
recommended for the same pathology and are thus potentially taken at the same time. For example, vitamin E
supplements, which are often recommended to patients with atherosclerotic vascular disease, may have an
interaction with statin drugs (Brown et al., 2001).
Disease or pre-existing conditions, such as hypertension, cardiac arrhythmias, or other early stages of
cardiovascular disease, can also be expected to exacerbate susceptibility to products that specifically affect the
organ exhibiting the disease or condition. Another example is the potential for supplements that affect insulin
and glucose regulation to affect persons with diabetes. Thus, factors such as age, disease, pre-existing conditions,
ethnicity, gender, or history of specific xenobiotic exposure such as pesticides can alter supplement exposure by
altering pharmacodynamics and clearance of a drug. Alternatively, these factors may alter the dose-response,
causing certain individuals to be more sensitive to a specific supplement than the majority of the population.
The paragraphs above describe several general reasons for particular susceptibilities. In addition, special
concerns are warranted for supplement ingredients that may have teratogenic effects. Fetuses may be harmed if
exposed to dangerous substances in utero as may infants if exposed to substances released into human milk. A
well-known example is the teratogenicity of high doses of vitamin A and related retinoids in the periconceptual
period (Eckoff and Nau, 1990; Lammer et al., 1985; Rothman et al., 1995). Animal studies or chemical
characteristics may provide clues that fetuses or infants are particularly susceptible to other supplement
ingredients as well.
72
In summary, certain segments of the population may be particularly susceptible to the effects of some
supplement ingredients for a variety of reasons. When reviewing data, it is important to ask if ingredients are
more likely to cause harmful effects to particular subgroups of the population. In the proposed framework,
“vulnerable groups” are described as a modifying factor, in that whether identifiable subpopulations are
particularly susceptible to harm should always be taken into consideration when assigning screening and prioritysetting scores (see Chapter 5 for more details).
Vulnerable Subpopulation Information as a Modifying Factor in the Screening/Flagging Step
In examining the human data used to screen/flag dietary supplement ingredients, the reviewer should
consider if the dietary supplement ingredient is being used by subpopulations that are particularly susceptible to
serious adverse effects.
Vulnerable Subpopulation Information as a Modifying Factor in the Priority-Setting and Critical Safety
Evaluation Steps
Particular susceptibility of identifiable subgroups of the population is taken into account when considering
the scientific evidence (human, animal, structure/chemotaxonomy, and in vitro evidence) in this step, as noted in
the description of scoring provided in Chapter 5.
GUIDING PRINCIPLE FOR VULNERABLE SUBPOPULATION DATA
When data indicate that an identifiable Subpopulation may be especially sensitive to adverse
effects from a certain supplement ingredient, then this higher level of concern should be taken into
account when scoring the ingredient.
New Ingredient Status
A new dietary supplement ingredient is one that was introduced to the U.S. market after October 1994,
when the Dietary Supplement and Health Education Act was implemented. In this proposed framework, the
notification of intent to market a new dietary supplement ingredient by a manufacturer automatically moves the
ingredient through the screening/flagging step and on to the priority-setting step. Noting new ingredient status
allows the ingredient to be considered during the priority-setting process in relation to other new ingredients and
other ingredients flagged in the first step of the process.
If the new ingredient has been used in other countries there may be a considerable amount of clinical,
animal, and in vitro data; data on serious adverse events; or data on usage patterns. If this type of information is
not available, it is expected that considering the biological activity of related substances will be helpful in setting
priorities in Step Two of the process. If the new dietary supplement ingredient is marketed after the 75-day
notification period, more data may become available, and the priority level of the ingredient may change.
The rationale behind channeling all new ingredients directly into the priority-setting process is that the
limited information on the other factors, especially human data, is no indication of
73
safety because the ingredient has not been marketed in the United States. Thus, the direct channeling of all new
products to the priority-setting step assures that scientific data and theoretical prediction of harm are considered
by the framework to some degree.
Use of New Ingredient Status in the Screening/Flagging Step
Consideration of new ingredient status in the screening/flagging step does not require that FDA actively
collect information. The 75-day notification, which comes to FDA directly from the manufacturer, indicates that
the item should be flagged and moved forward to the priority-setting step, simply by virtue of being a new
ingredient about to enter the market.
Use of New Ingredient Status in the Priority-Setting and Critical Safety Evaluation Steps
New ingredient status is not considered in the priority-setting step or in the critical safety evaluation of an
ingredient. The new ingredient status simply moves it into the priority-setting process, where the evaluation of
evidence of the other key factors occurs.
SUMMARY
In summary, several different key factors and modifying factors should be taken into consideration when
evaluating the safety of dietary supplement ingredients. The four primary key factors (data from humans and
clinical evidence of harm, animal data, bioactivity of structurally related and taxonomically related substances,
and in vitro data) contribute to different extents in the two first steps of the proposed process, screening/flagging
and priority-setting, as compared to their contribution to the third step, the critical safety evaluation. The same
holds true for the two modifying factors (prevalence of use in the population and use by vulnerable
subpopulations). In Chapter 5, the processes for screening/flagging and priority-setting are described, with more
suggestions about how different types of data are appropriately weighted when setting priorities. A systematic
approach to this weighting process is described. After ingredients are categorized and prioritized, in-depth safety
evaluations should be conducted for the ingredients with the greatest safety concerns (and which thus have the
highest priority scores). Chapter 6 outlines a system for conducting these reviews and also revisits the guiding
principles underlying the consideration of different types of data that were first outlined in this chapter.
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5
Framework Steps One and Two: Screening/Flagging and
Priority Setting
The proposed framework begins the evaluation of the safety of dietary supplement ingredients with a
process of screening each ingredient and then flagging those that should receive highest priority for an in-depth
critical safety evaluation. Using the factors described in Chapter 4, it is possible to utilize readily available
information resources to aid in identifying those dietary supplement ingredients that warrant further evaluation
and to prioritize them for the evaluation process. In this chapter the proposed general approach to setting
priorities for review is described, followed by a discussion of how screening and priority setting can be done. It
is assumed that the screening/flagging and priority-setting steps will be completed by Food and Drug
Administration (FDA) staff, but FDA may instead choose to contract these processes out to a suitable
scientifically based organization.
GENERAL APPROACH
The initial goal of the framework is to organize the factors described in chapter 4 into a structure that
enables regulators to focus on the supplement ingredients that require the most attention. A three-step framework
is proposed to focus such efforts. The three-step process consists of (1) screening and flagging based on readily
available information, (2) priority setting based on analysis of available information, and (3) critically evaluating
the data regarding safety of supplement ingredients. It is designed to help FDA first make initial judgments that
reduce the large number of ingredients currently in the U.S. marketplace to a manageable number. The
ingredients are then categorized by priority based on the greatest likelihood of potential harm. This will allow
FDA to focus on conducting in-depth critical safety assessments for ingredients determined to be of high priority
(Step 3, described in Chapter 6).
As was discussed in Chapter 4, data regarding key factors are used in one or more of the steps of the
framework, but there are differences in how the different factors, modifiers, and new ingredient status are
considered in each of the three steps. For example, new ingredient status is assigned an integral place in the
screening/flagging step, but it plays no role in the subsequent safety assessment. In contrast, there are also factors
that are not explicitly considered as discrete factors in the screening/flagging step but which may play an integral
role in the priority-setting or critical safety evaluation steps.
78
In summary, the goal of Step One, screening/flagging, is to identify those supplement ingredients that could
possibly cause harm. The goal of Step Two, priority setting, is to determine which of the ingredients identified in
the screening/flagging step are of the highest concern and should therefore be placed at highest priority for a full
evaluation. The goal of Step Three, critical safety evaluation (discussed in Chapter 6), is to provide a detailed
review of what is known about the theoretical and demonstrated safety of a dietary supplement ingredient that
would allow FDA to determine if further action is needed in regulating the ingredient in the marketplace.
STEP ONE: SCREENING/FLAGGING
The screening/flagging step was developed on the premise that it is not feasible for FDA to immediately
search extensively for information about every dietary supplement ingredient. Readily available information can
be used to flag substances that warrant further attention while maintaining enough sensitivity to minimize false
negatives and not omit any items with potential safety concerns.
To flag substances warranting some level of attention, “yes or no” questions were developed to identify
ingredients that should move forward to Step Two, the priority- setting step. A “yes” answer to any of the
following questions flags the dietary supplement ingredient and moves it on to Step Two.
1. Has a 75-day new ingredient notification been filed with FDA?
2. Are there serious adverse events reported through MedWatch, poison control centers, or clinical
studies that illustrate a pattern in terms of the type of incident reported, that are well-documented in
the medical literature, or that may be plausibly linked to the dietary supplement ingredient? Or, does
the number of serious adverse events reported appear high compared to the ingredient's prevalence
of use? Or, does it seem plausible that particular subpopulations are particularly susceptible to
serious adverse events reported for this dietary supplement ingredient?
3. Has the ingredient been brought to FDA's attention because of concerns other than new ingredient
status or human adverse event data described above? (A preliminary evaluation of concerns that
have come to FDA's attention will allow PDA to determine which of these ingredients should move
into the priority setting process.)
The following are examples of “other concerns” that may bring an ingredient to FDA's attention for
screening and possibly flagging, but this list is by no means exhaustive:
• Safety concerns from other groups or organizations that have evaluated substances currently on the
market as dietary supplement ingredients. Examples of such safety concerns include compounds
previously evaluated as drugs (including over-the-counter drugs), regulatory actions from other
governments (e.g., Commission E), usage levels greater than the tolerable upper intake level values set
by the Dietary Reference Intakes process (IOM, 1998), and information released by the Office of
Dietary Supplements, National Institutes of Health.
• Strong evidence of serious interactions with prescription drugs.
• Evidence that the ingredient mimics hormonally active compounds.
79
• Communications, such as letters describing potential public health problems associated with a particular
ingredient, brought to FDA's attention via consumers, consumer representative organizations, or
scientific organizations. Likewise, this type of concern may come to FDA's attention through media
coverage of a public health problem or new experimental data.
In some cases, reports coming to FDA through any of these mechanisms may indicate that contamination or
adulteration of a dietary supplement ingredient may be associated with serious adverse events. Such cases should
be directed to the section of FDA handling Good Manufacturing Practice issues for dietary supplement
ingredients, rather than moving the ingredient forward to the priority-setting process in this framework.
In keeping with the philosophy that the screening/flagging step should be relatively simple and
straightforward, answering the three screening questions does not involve evaluation or weighting of the
evidence. A “yes” to any of the questions is sufficient to move the ingredient to the next step. The rationale for
the questions is explained below.
New Ingredient Status
New ingredient status is the most straightforward of the screening questions. The reviewer asks if the
ingredient is a new ingredient, marketed after the Dietary Supplement Health and Education Act (DSHEA) was
enacted (after October 1994). According to DSHEA (see Chapter 1), FDA is to be notified of all ingredients new
to the United States 75 days before they are marketed, so this information is readily available. As described in
Chapter 4, the rationale for flagging all new ingredients and moving them to the priority-setting process is that
(1) they are less likely to be associated with a history of safe use, and (2) there has been little opportunity for
serious adverse events to surface, at least in the United States. There is also likely to be less scientific research on
these ingredients, although this may not always be the case.
Human Data
Human data is the first key factor considered. In the screening/flagging step, upon learning of serious
adverse events from a number of sources such as FDA's MedWatch reporting system, poison control center
databases, published clinical studies and case reports, or secondary reviews of safety information, FDA flags the
dietary supplement ingredient involved and moves it forward to the priority-setting process. Adverse events that
warrant consideration are those that are “serious,” as defined in Chapter 4. FDA makes an initial judgment about
the reported events, but does not attempt to determine if there is causation or to validate the reports at this stage
in the framework. To determine which ingredients are moved forward to the priority-setting step, FDA looks tor
possible patterns in the type of events reported, for well-documented reports, and for reports that suggest a
linkage between the ingredient and the event is at least plausible. Importantly, at this screening step, the reviewer
asks whether the data suggest a possible problem rather than focusing on making a definitive judgment. While
this strategy has the potential to overestimate ingredients causing possible harm, it is important to be inclusive at
this point in the process.
In this preliminary evaluation of human data on serious adverse events, some consideration should be given
to the usage patterns of the ingredient in question. Ingredients for which the number of serious adverse events
relative to the prevalence of use seems high should be moved
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forward. Likewise, the pattern of vulnerable group use should also be considered if data regarding their use come
forward. If an ingredient is particularly marketed to, or preferentially used by, a particular subpopulation, and
human data suggest particular susceptibility of this subpopulation to the biological action of the ingredient, it
should be moved forward to the priority-setting step.
Other Concerns
The third screening category, “other concerns,” recognizes that information regarding safety will come to
FDA's attention for reasons other than new ingredient status or serious adverse events in humans. As discussed
earlier, it is important for FDA to take advantage of sources of information that do not require detailed and timeconsuming searches. Consumer protection organizations and the media bring forward information that they
believe warrants FDA attention. This screening question allows FDA to consider this input and other concerns
that come to its attention without judging the quality until it is examined more thoroughly in the priority-setting
step.
FDA may also learn about other possible safety problems by perusing the safety concerns of other
evaluative groups. For example, information can be gleaned about ingredients previously considered by other
governments (e.g., Commission E in Germany), organizations conducting secondary reviews (e.g., the World
Health Organization [WHO, 1999]), and texts describing historical patterns of use. The accuracy and reliability
of the different secondary sources as arbiters of safety information may vary considerably, but when concerns
are raised they warrant consideration.
It is not possible to list all the possible concerns that warrant moving an ingredient forward for
consideration in the priority-setting step, but there are a number of concerns that definitely should flag a dietary
supplement ingredient when FDA becomes aware of them. These include ingredients that mimic hormonally
active compounds and ingredients that may interact with prescription drugs.
In summary, the screening questions given above are designed to use readily available information sources
to flag ingredients for consideration in the priority-setting step. Information pertaining to serious adverse events
in humans will require FDA to actively and regularly search primary information sources, but new ingredients
and other concerns will either come to FDA's attention directly or will require only minimal informationgathering activities.
STEP TWO: PRIORITY-SETTING PROCESS
The goal of the priority-setting process is to identify those dietary supplement ingredients that require the
most immediate attention of FDA for a more in-depth safety evaluation. The priority-setting process differs from
the initial screening process in four fundamental ways:
• additional factors are considered;
• additional information about each factor is obtained through more active searching;
• a more evaluative judgment about the strength of the evidence and the level of potential harm is made;
and
• the different factors are weighted differently, based on their comparative importance.
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Thus, the most fundamental difference is that as a dietary supplement advances at each step in the process,
it requires more information and there must necessarily be more evaluative input.
The factors to be used in the priority-setting process include:
•
•
•
•
•
human data;
animal data;
biological activity of structurally related and taxonomically related substances;
in vitro data suggesting potential risk of harmful effects; and
prevalence of use.
It is assumed that FDA staff with enough experience to make initial judgments regarding the level of
evidence of possible risk and seriousness of potential effects will conduct this activity. It is possible, however,
that FDA may want to contract with a suitable scientifically based organization to conduct the priority-setting
process.
General Description of How to Score Information
In the priority-setting process (Step Two), a sorting matrix can be used to categorize the variety of
dissimilar ingredients according to their relative priority for review. For each of the supplement ingredients
flagged in the screening process, the information for each of the four key factors (human data, animal data, data
about the bioactivity of related substances, and in vitro data) is reviewed and assigned a score. These scores are
0, 1, 2, 3, or NAD when no appropriate data are available to evaluate the information. The four scores (one for
each factor) for each ingredient are entered into a matrix (see Table 5–1).
The numerical scores are designed to reflect a judgment of the potential seriousness, and therefore
relevance, of the physiological effect and the evidence of possible risk, which is derived from both the quantity
and quality of the evidence reviewed. Specific guidelines are outlined for each factor later in the following
section, but in general, the following scoring guidelines are employed, as illustrated in Figure 5–1:
• A score of 3 is assigned for each factor where the data suggest both a potentially serious and very
relevant harm and where there is a strong evidence of possible risk, or there is strong evidence
suggesting a possible serious drug interaction.
FIGURE 5–1 Scoring system.
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• A score of 0 is assigned when there is strong evidence that there is no serious harm.
• A score of NAD is assigned when no appropriate data are available.
Scores of 1 and 2 are not explicitly defined but result from a judgment of the potential seriousness of the
physiological effect and the evidence of possible risk. This is illustrated in Figure 5–1. For background
information on each of the factors, including discussions of what constitutes strong evidence of possible risk, see
Chapter 4.
As the information about a number of ingredients is scored, more cells of the priority-setting matrix are
filled, as shown in Table 5–1 for fictitious ingredients. The matrix serves as an increasingly useful informational
database for classifying information about the different ingredients. The matrix structure also enables the
ingredients to be sorted based on their relative priority for further in-depth review. This sorting is described
below, following the description of the relative priority of scores for each factor.
TABLE 5–1 Matrix of Scores Used in Establishing Relative Priority Among Dietary Supplements
Human Data Animal Data Biological Activity of Structurally Related or
Ingredient Name
Taxonomically Related Substances
Yellow plant extract 3
1
2
Vitamin X
2
NAD
2
Animal tissue
2
1
1
a
In Vitro Data
2
NADa
1
NAD=no appropriate data.
Which Scores Indicate Higher Priority
A number of different sorting schemes could be developed to produce a ranking of ingredients categorized
in order of priority for a full safety evaluation. The committee, recognizing that weights assigned to different
factors could easily be arbitrary, deliberately chose not to assign explicit quantitative weights to the factors other
than hierarchical ranking. In the proposed scheme, ingredients are ranked and categorized into priority groups by
a sorting mechanism that reflects the hierarchical value of the different key factors. When available, concerns
raised by human data are weighted more heavily than animal data, and are thus given higher priority. Concerns
raised by either human or animal data are given greater weight than concerns raised by bioactivity of related
substances or in vitro data, which are weighted equally.
Scores of 3 represent greater concern and therefore rank higher than scores of 2, 1, or 0. NAD scores always
rank higher than 0. Because a score of 0 indicates that there is evidence suggesting no serious harm, and a NAD
score indicates that there is no evidence, it is clear that NAD scores represent more reason for concern than
scores of 0.
Does an NAD score cause more concern than some evidence of harm, as would be indicated by a score of 2
or 1? In the model presented here, a score of NAD is sorted as warranting more concern than a score of 1, but
less concern than a score of 2 (e.g., as if it is assigned a value of 1.5). There are two exceptions to this rule: if
either the data about bioactivity of related substances or animal data are scored as a 3, then a NAD score for
human data is sorted as if it falls between scores of 2 and 3 (e.g., as if it is assigned a value of 2.5). How NAD
scores are sorted compared to the numerical scores is summarized here:
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• human data: 3, 2, NAD, 1, 0 if neither animal data nor bioactivity of related substances are scored as 3; or
3, NAD, 2, 1, 0 if either animal data or bioactivity of related substances are scored as 3
• animal data: 3, 2, NAD, 1, 0
• bioactivity of structurally related or taxonomically related substances: 3, 2, NAD, 1, 0
• in vitro evidence: 3, 2, NAD, 1, 0.
The sorting methodology can be further illustrated with examples. The following list indicates how an
ingredient with a score of NAD in animal data would be sorted in comparison to three other ingredients. The
ingredient with a score of NAD is sorted as if the NAD had a value of 1.5:
2–2–2–3
2–2–2–3
2-NAD-2–3
2–1–2–3
The following list illustrates how an ingredient with a score of NAD for human data and a 3 for animal data
is sorted compared to three other ingredients. Because the animal data is a 3, the NAD value is given more
weight and the ingredient with a score of NAD is sorted as if the NAD had a value of 2.5:
2–3–3–3
2-NAD-3–3
2–2–3–3
2–1–3–3
To further illustrate the sorting methodology, all possible scoring combinations are listed in order of priority
in Appendix C.
Ranking Ingredients Within the Matrix: Using Scores to Sort Ingredients Into Priority Groups
The proposed mechanism for categorizing dietary supplement ingredients considers the scores for each
factor to sort ingredients into priority categories named Priority Group I, Priority Group II, Priority Group III,
and so on. These priority groups are illustrated in Table 5–2. The proposed sorting mechanism reflects the
hierarchy of the different types of relevant scientific data reviewed (i.e., human data>animal data>data about
bioactivity or structurally related and taxonomically related substances=in vitro data). It places highest priority
on the ingredients for which there is strong human and animal evidence of possible risk of serious adverse events
or serious drug interactions (i.e., scores of 3). Next priority is given to ingredients for which there is strong
human data evidence of possible risk of serious adverse events or serious drug interactions, and then to
ingredients for which there is strong evidence from animal studies of possible risk of serious adverse events or
serious drug interactions, and so on.
This rationale is numerically reflected in the sorting of scores. First, dietary supplement ingredients with
scores of 3 in the human data and animal data factors are grouped into Priority
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Group I. There are 25 different score combinations that would be included in this priority group. Within Priority
Group I, the 25 score combinations are ranked according to their scores in the bioactivity of related substances
and in vitro data. These details are apparent in the in-depth scheme provided in Appendix C, which lists all
possible combinations of scores and ranks them by priority.
TABLE 5–2 Matrix for Priority Establishment Based on Factor Analysis
In Vitro
Priority Group Human Data Animal Data Bioactivity of
Structurally Related Data
or Taxonomically
Related Substances
I
3
3
Number of
Combinations
(Total=625)
Characteristics of
Priority Group
25
II
III
IV
100
100
144
Two 3s in first two
factors
3 in human data
3 in animal data
One or two 3s in
structure/ taxonomy
or in vitro factors
No 3s in any key
factor
V
3
3
3
3
256
Priority Group II includes ingredients with a score of 3 in the human data factor and less than 3 in the
animal data factor. The 100 different score combinations within Priority Group II are sorted based on the scores
in animal data, bioactivity of related substances, and in vitro data. Priority Group III includes ingredients that
scored a 3 in the animal data section and less than 3 in the human data factor. Priority Group IV includes
ingredients that have a score of 3 in the bioactivity of related substances factor or the in vitro factor. Finally,
Priority Group V ingredients are ingredients that did not score a 3 in any of the categories. Within Priority Group
V, ingredients are ranked as described above; that is, more weight is placed on human data, less on animal data,
and even less on data about bioactivity of related substances and in vitro data. If, with use of this system, Priority
Group V is found to encompass too many ingredients to be helpful, it could be further divided into subgroups
V-1, V-2, and so on, following the pattern for defining the other priority groups.
All theoretically possible scores and how they fit into the different Priority Groups are listed in Appendix C.
A number of these combinations of scores, or composite scores, are unlikely to occur because the combinations
of data they represent are expected to occur infrequently, if at all. For example, the composite score of 0–0–0–3
(Priority Group IV) would be unlikely to occur very often, given the conflicting nature of the data that must exist
to derive this score. That is, a 0–0–0–3 indicates that there are strong human data, animal data, and data about
related substances, implying the ingredient causes no serious harm, but there is also strong in vitro evidence of
harm in a highly predictive in vitro assay and evidence that harmful ingredients may reach sites of action where
they can cause harm. At first glance the current approach might seem to inappropriately allow the in vitro data
alone to place this theoretical ingredient in the Priority Group IV, but if this scenario does exist, the higher
Priority Group IV classification provides an
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opportunity for FDA to consider the disparity presented by the information before considering ingredients in
Priority Group V with scores of 2s but no 3s.
Prevalence of Use: A Modifier of Sorting Within Priority Groups
Within each priority group, the prevalence of use is considered as a modifier of the available data.
Ingredients with relatively high prevalence of use are shifted to the top of the ranked list within each priority
group, so that they will receive attention first before those in the same priority group. “Relative prevalence of
use” cannot be precisely defined, but it is suggested that lists of sales data and surveys about the use of particular
ingredients be consulted, as described in Chapter 4.
Specifics on Assigning a Score for Each Factor
More information about assigning a score to each of the ingredients is provided below. Some examples for
what is considered a higher priority (a score of 3) and what is considered a lower priority (a score of 1) are
presented, recognizing that judgment comes into the process of scoring. Although judgment is important in
setting scores, the scoring process enables the reviewers to consider the different factors independently and
individually for each ingredient, taking advantage of all the data that are available. The system also enables FDA
to develop an overall ranking for each ingredient—a ranking that is dynamic and can shift when more
information becomes available. Finally, one could imagine that the composite scores of ingredients (such as 3–1–
2–2 for the yellow plant extract in Table 5–1) might be used internally to summarize the preliminary information
collected in the priority-setting step.
Scoring Human Data
Human data are considered from a different perspective in the priority-setting process, as compared to how
human data are considered in the screening/flagging step. As with all the factors, the information is scored based
on the potential seriousness of the harm and the evidence of possible risk. In the screening step, however, the
effort is focused on examining evidence of only serious adverse events (as defined in Chapter 4), while in the
priority-setting step all evidence of adverse events in humans is considered. Another difference is that in the
priority-setting step, more time is invested in assessing the evidence that suggests adverse events. It will also be
necessary to consider the human data for ingredients that were flagged for reasons other than evidence of serious
adverse events in humans.
As shown in Figure 5–1, evidence of possible risk is considered in scoring human data. At this point in the
framework, sufficient resources are unlikely to be available to determine causation, but the general guidelines
outlined in Chapter 4 for considering causation should guide the judgment of the data quality and quantity.
The seriousness of the adverse effects or potential interactions is also important in scoring. In addition to
considering the seriousness of potential harm to the general population and the strength of the data suggesting
potential harm to the general population, it is also important to consider how particular subpopulations might be
particularly vulnerable to adverse effects from the ingredient (as described in Chapter 4).
The following descriptions should be used as guidelines to score the human data, bearing in mind that some
judgment is involved in scoring:
86
• A score of 3 should be given if there is strong evidence that there is a possible risk of potentially serious
adverse effects or potentially serious drug interactions. For example, well-documented cases of
potentially serious adverse events in the medical literature, a strong pattern of similar potentially
serious adverse events in MedWatch, action against a dietary supplement ingredient by another
country's regulatory authority, clinical studies indicating potentially serious drug interactions, or
multiple -well-documented case reports of potentially serious drug interactions.
• Scores of 1 and 2 fall between 3 and 0 and thus are notably more subjective. Using Figure 5–1 as a
guide, a score of 2 would be appropriate in a situation where the evidence of possible risk is limited but
the potential harm is serious. Likewise, a score of 1 might be appropriate in situations when there is
some evidence of possible risk, but the potential risk does not appear to be very serious.
• A score of 0 should be given if there is strong evidence suggesting no potential serious harm and no
potential serious drug interactions (in most cases it is not anticipated that information about historical
use would provide strong enough evidence to warrant a score of0).
• A score of NAD should be given if there is no appropriate data available to evaluate.
Scoring Animal Data
The consideration of animal data in the priority-setting step is very different from the consideration of
animal data in the screening/flagging step. In the screening/flagging step, animal data are only considered if they
come to FDA's attention. In contrast, FDA needs to actively look for the data in the priority-setting step. In this
step, the scientific literature should be systematically searched for evidence of harmful effects in animal studies
for all flagged ingredients. Sources for primary scientific literature include IBIDS, MedLine, Toxline, and other
scientific literature databases. Other databases that focus particularly on natural ingredients (e.g., NAPRALERT)
may also be useful for searching for evidence of adverse effects in animals. Finally, it is important to consult
secondary or tertiary reviews that may cite older or foreign data that might otherwise be difficult to uncover
using databases that do not capture pre-1960s or non-English literature. Reviews that may be helpful include
those listed in Table 4–1.
After gathering information, the evaluation of animal data should be concerned with the same two
components considered for human data: the evidence of possible risk, of which the quality and quantity of the
data are components, and the seriousness of the harm. While all whole animal experiments may be informative,
the nature of the experimental design, the quality of the methodology, and the statistical significance of the
results need to be taken into consideration in scoring the evidence. When considering seriousness of harm,
animal studies that predict serious harm or death warrant more attention, and thus higher scores, than those that
predict mild, self-limiting effects on humans. It is not practical to list all animal data that predict serious effects
in humans, but it is important to note that certain types of animal data should be considered serious because
associations between these effects and consumption of particular ingredients are likely to be much more evident
in animals than in humans. These effects include evidence of cancer, reproductive system effects, or
developmental toxicity effects, including teratogenicity or other harm to fetuses.
Ingredients for which data indicate serious effects are scored higher than those with potentially less serious
effects. Likewise, ingredients for which the evidence of risk is stronger
87
are scored higher than those with weaker evidence of possible risk. As discussed in Chapter 4, the strongest
animal data result from experiments in which the ingredient is orally administered in a form similar to that used
by humans. This characteristic is reflected in the scoring definitions below. As with human data, it is also
important to consider how vulnerable subpopulations may be particularly susceptible to adverse effects observed
in animals. The scoring guidelines outlined for animal data are analogous to those given for scoring human data:
• A score of 3 should be given if there is strong evidence that there is a possible risk of potentially serious
adverse effects or potentially serious drug interactions. Strong evidence is generated by experiments in
which the ingredient is orally administered in a form similar to that used by humans. Serious harm
includes effects that would eventually be reported as serious adverse events in humans and those effects
that would not be readily detected from general human use or clinical trials.
• As outlined earlier for human data. Figure 5–1 provides general guidance in judging whether a score of
2 or 1 is appropriate. A score of 2 would be appropriate in a situation where the evidence of potential
risk is limited but the potential harm is serious.
• A score of 0 should be given if there is strong evidence suggesting no potential serious harm and no
potential serious drug interactions.
• A score of NAD should be given if there are no appropriate data available to evaluate.
Scoring Data on the Biological Activity of Structurally Related and Taxonomically Related Substances
A dietary supplement ingredient may be structurally related or taxonomically related to substances with
biological activity that cause concern. As with animal data, this type of data will be considered in the screening/
flagging step if it comes to FDA's attention. In the priority-setting step, if the chemical structure of a dietary
supplement ingredient or its component chemical compounds is known, FDA should actively look for
information to determine if structurally related or taxonomically related substances are of known toxicological
concern. This type of information can be gathered from sources such as Medicinal Chemistry Reviews or other
journals. Chemicals that act as agonists or antagonists at the same receptors or other biological targets are likely
to produce similar effects and should be considered as related chemicals, even if they are not structurally related
in the strictest sense.
As described in Chapter 4, the plant genus itself may also provide clues about adverse effects. In the case of
botanical dietary supplement ingredients, several key sources of information about plants should be consulted in
the priority-setting stage. Texts that list poisonous plants by plant family, genus, and species are helpful in
identifying harmful ingredients. Poisonous Plants of the United States and Canada (Kingsbury, 1964) lists
egregious examples of harmful plants and also contains information helpful in identifying related plants.
Additionally, several databases (e.g., NAPRALERT) provide pharmacological and toxicological information
about plant compounds, which is helpful in identifying potentially dangerous substances by the taxa of botanicals.
When scoring information about the biological activity of structurally related or taxonomically related
substances, several considerations are important:
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• the ingredient's similarity in structure or taxonomic relatedness to a known harmful substance;
• the seriousness of harm caused by ingesting related substances; and
• the strength of the evidence suggesting that the related substance does cause harm.
Taken together, these components allow the data about the biological activity of related substances to be
scored (see below). As in the case of other factors, scoring of this factor should take into account if and how a
predicted adverse effect might particularly affect vulnerable subpopulations.
Scoring for the biological activity of related substances is analogous to the scoring schemes outlined for the
factors above:
• A score of 3 should be given if the ingredient has the same or similar structure, or putative biological
target (e.g., receptor) as a known compound that causes potentially serious adverse effects or
potentially serious drug interactions. Or, the plant-derived dietary supplement ingredient is of a related
species and same genus as a plant for which there is strong evidence of possible risk for potentially
serious adverse effects or potentially serious drug interactions.
• As outlined earlier for human and animal data, Figure 5–1 provides general guidance in judging whether
a score of 2 or 1 is appropriate. A score of 2 would be appropriate in a situation where the evidence that
a related structure or plant causes harm is limited, but the potential harm is serious. Likewise, a score of
1 might be appropriate in situations when there is some evidence of possible risk, but the risk does not
appear to be potentially very serious.
• A score of 0 should be given if there is strong evidence suggesting no structurally related or
taxonomically related ingredient that causes serious adverse events or drug interactions.
• A score of NAD should be given if there is no available evidence about the structure of the substance or
its taxonomy, or the biological activity of structurally related or taxonomically related substances.
Scoring In Vitro Data
In vitro data collected on flagged ingredients are scored in the priority-setting step in the same manner as
the other factors described above. Information about in vitro effects can be obtained from the same sources as
those for animal data (see Table 4–1). These sources include literature databases, other databases, and secondary
and tertiary reviews.
In vitro data are considered in terms of the evidence of possible risk and the potential seriousness of harm
suggested by the data. Predictive value is also considered for in vitro data; assays that strongly correlate with
animal or human outcomes that are very harmful or serious are scored higher.
Scoring for in vitro data is as follows:
• A score of 3 should be given if there is strong in vitro evidence that there is a possible risk of potentially
serious adverse effects or potentially serious drug interactions. Strong in vitro evidence consists of (a)
data from a validated assay that strongly predicts in vivo
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outcomes that are potentially serious or predictive of potentially serious drug interactions and (b)
evidence that the potentially harmful substances are bioavailable. Examples of results from validated
assays may include inhibition of mitochondrial oxidative phosphorylation, substantial cytochrome P450
inhibition, and evidence of slowed cardiac repolarization.
• As outlined for human and animal data, Figure 5–1 provides general guidance in judging whether a
score of 2 or 1 is appropriate. A score of 2 might be appropriate when the evidence of possible risk is
limited but the potential harm is serious. Similarly, a score of 1 might be appropriate in situations where
there is some evidence of possible risk, but the potential harm does not appear to be serious.
• A score of 0 should be given if there is strong evidence suggesting no potentially serious harm and no
potentially serious drug interactions.
• A score of NAD should be given if there is no appropriate data available related to in vitro assessment.
SUMMARY
In summary, each type of information available (human data, animal data, data about the biological activity
of structurally related or taxonomically related substances, and in vitro data) is scored. These scores are derived
by considering what the available information reveals about both the evidence of possible risk and the potential
seriousness of harm. These scores are used to sort the dietary supplement ingredients into priority categories
based on their priority for further safety evaluation. The result of the priority sorting may be modified by
information on the prevalence of use.
REFERENCES
IOM (Institute of Medicine). 1998. Dietary Reference Intakes: A Risk Assessment Model for Establishing Upper Intake Levels for Nutrients.
Washington, DC:National Academy Press.
Kingsbury JM. 1964. Poisonous Plants of the United States and Canada. Englewood Cliffs, NJ: Prentice-Hall.
WHO (World Health Organization). 1999. WHO Monographs on Selected Medicinal Plants, Volume I. Geneva: WHO.
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FRAMEWORK STEP THREE: CRITICAL SAFETY EVALUATION OF DIETARY SUPPLEMENT INGREDIENTS
91
6
Framework Step Three: Critical Safety Evaluation of Dietary
Supplement Ingredients
The screening/flagging and priority-setting steps outlined in the previous chapters will result in the
identification of a group of dietary supplement ingredients that are of highest priority for further evaluation. This
further evaluation requires the collection of additional information and critical analysis of the available safety
data by the Food and Drug Administration (FDA) (Step 3 A), and then, if appropriate, analysis by an advisory
committee (Step 3B). The process for this evaluation is described in this chapter. As with the two earlier steps of
the process, these two steps may be organized by FDA or contracted out to an appropriate scientifically based
organization.
STEP 3A: DRAFT MONOGRAPH PREPARATION AND REVIEW BY THE FOOD AND
DRUG ADMINISTRATION
Step 3 A includes the preparation of a draft monograph and review of this monograph by FDA to determine
if further input should be solicited. It is assumed that resources will initially be allocated to preparing
monographs for substances ranked as higher priority in Step Two.
The process for Step 3A begins with completing the data collection (see Figure 3–1). Data will already have
been obtained during the priority-setting step, but efforts should now be expanded to more comprehensively and
systematically search for relevant information. The general types of information to be collected are listed in
Box 6–1 (the monograph format) and include a description of the ingredient (e.g., constituents, different types of
preparations, active components, traditional indications) and available information about toxicities and safety
(human data, animal data, data describing the biological activity of structurally related or taxonomically related
substances, in vitro data, and questions raised about the safety of the ingredient). Table 4–1 in Chapter 4
describes resources to be consulted in gathering safety information for this step, but this description is not
exhaustive. For example,' additional information may be obtained by requesting information from clinical
investigators who have published reports about the particular ingredient. Additional information may also be
obtained from industry (e.g., distributors and manufacturers). At this stage in the review, there is sufficient
concern about the safety of the ingredient to justify FDA's requesting that more safety data information be
volunteered by industry. This request may be made through notice in the Federal Register and through the FDA
website as a means to make the need for more information widely known to the
92
public. FDA should also directly request information from the manufacturers and distributors of the ingredient
under consideration to the extent that manufacturers and distributors are known.
BOX 6–1 SAFETY REVIEW: MONOGRAPH FORMAT
I.
II.
INGREDIENT NAME
DESCRIPTION OF THE INGREDIENT, which includes the following:
• Constituents as appropriate: chemical structure; for a botanical ingredient, genus, species, part of plant
• Examples of products known to contain the ingredient
• Descriptions of different preparations (include U.S. Pharmacopeia process if available; country of origin,
if known)
• Range of typical intake levels (where known, this will include recommended intake levels and data on
actual intake)
• Description of active components, if known
• Traditional indications, if applicable
• Claim (label or other marketing information)
• Usage patterns (prevalence of use in the general population, use by vulnerable groups, use in
combination with other ingredients)
III.
•
•
•
•
IV.
V.
AVAILABLE SAFETY INFORMATION AND EVALUATION
Human data (serious and nonserious adverse effects)
Animal studies
Biological activity of structurally related and taxonomically related substances
In vitro studies
RESEARCH NEEDS
CONCLUSIONS
• Unresolved issues and uncertainties in the available data
• Recommendations and conclusions about the safety of the ingredient, based on the strength of the
scientific evidence
VI.
CITATIONS (including citations and hard copies of references used)
The collected information should be collated into a “draft dietary supplement ingredient safety review
monograph,” or simply “draft monograph.” The monograph should be prepared using a standard format to
summarize all the data collected on the ingredient (see Box 6–1 for an outline of the monograph structure).
After the draft monograph is prepared, FDA should consider the totality of the scientific evidence obtained.
FDA should decide, based on the weight of the evidence, if the evidence is sufficiently clear to allow the product
to remain on the market or if it is sufficiently clear to take action to limit marketing the ingredient. The guiding
principles in Box 6–2, summarized from Chapter 4, should be followed for assessing and weighting the different
types of evidence that enter into the decision.
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BOX 6–2 GUIDING PRINCIPLES FOR CONSIDERING THE RELATIVE VALUE OF DIFFERENT
TYPES OF INFORMATION
• A credible report of a serious adverse event in humans that is associated with use of a dietary
supplement ingredient raises concern about the ingredient's safety and requires further
information gathering and evaluation. A final judgment about the safety of the supplement
ingredient, however, will require consideration of the totality of the evidence. Historical use
should not be used as prima facie evidence that the ingredient does not cause harm. It may be
appropriate, however, to give considerable weight to a lack of adverse events in large, highquality, randomized clinical trials or retrospective or prospective cohort studies that are
adequately powered and designed to detect adverse effects. The rationale for this statement is that
adverse events might only be detected if readily apparent or specifically searched for. A study that does
not systematically examine participants for adverse events and then publish this information is therefore
of little value. In addition, some studies have insufficient statistical power to detect adverse events of low
incidence.
• Even in the absence of human adverse events, evidence of harm from laboratory animal studies
can be indicative of potential harm to humans. This indication may assume greater importance if
the route of exposure is similar (e.g., oral), the formulation is similar, and more than one species
shows the same toxicity. Particular weight is placed on evidence of certain types of delayed effects
that are less likely to be detected in humans; these effects include cancer, teratogenicity, developmental
toxicity, and reproductive toxicity. This evidence warrants particular attention as these nonacute effects
are often only detectable in animals (as opposed to humans) because large doses can be administered
subchronically or chronically to predict delayed effects following chronic exposure in humans.
• The presence of a constituent that is structurally similar to known toxic or potentially harmful
compounds or a plant that is taxonomically related to known toxic plants suggests increased
risk, and therefore higher priority, unless there is evidence that the compound is not toxic or
harmful, the compound is present in concentrations that will not lead to harm, or there is other
evidence supporting the safety of the ingredient.
• In vitro studies can serve as signals of potential harmful effects in humans, but not as
independent indicators of risk unless an ingredient causes an effect that has been associated
with harmful effects in animals or humans and there is evidence that the ingredient or its
metabolites are present at physiological sites where they could cause harm. Alone, in vitro data
should serve only as hypotheses generators and as indicators of possible mechanisms of harm
when the totality of the data from the different factors is considered.
After considering the draft monograph and the totality of the evidence in the context of the guiding
principles outlined above, FDA should either make a decision to take regulatory action, not to take regulatory
action, or to refer the dietary supplement ingredient to an advisory committee of multidisciplinary expe rts for a
safety review. Because only high-priority ingredients with significant potential for concern are likely to reach
this evaluation stage, it is expected that FDA may want further input from an advisory committee on a number of
dietary supplement ingredients.
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STEP 3B: CRITICAL EVALUATION BY AN EXTERNAL ADVISORY COMMITTEE
Unless FDA has internal scientists with the appropriate expertise, it may be cost-effective to create an
external advisory committee to provide further input on the safety of the dietary supplement ingredient. FDA
may choose to have external advisors participate for one of a myriad of reasons, including,
•
There is credible evidence that the ingredient may cause harm, but further review is needed by
consultants with specific knowledge about the ingredient to interpret the totality of the data and derive
conclusions and recommendations.
• Available evidence is of questionable scientific basis or difficult to interpret.
• Insufficient data are available to make decision-making obvious.
• A mechanism for public input is needed.
These reasons are only examples, as many other circumstances may trigger the decision for external
advisory committee review. The decision to refer a dietary supplement ingredient to an external advisory
committee rests with FDA and may be made for any reason that external expert opinion is deemed necessary or
cost effective. The external advisory committee opinions or conclusions should be based on the information and
data presented, but the decision on the regulatory consequences of the external advisory committee
determinations must rest with FDA.
The decision to refer an ingredient for external review requires that a standing external advisory committee
be established. To ensure that the critical evaluation of the monograph and related information is as free of
conflict of interest and as objective as possible, the external advisory committee should be composed of expert
scientists who, by training, education, and experience, constitute the most appropriate body to advise FDA.
Box 6–3 lists several types of expertise that should be included. Importantly, external advisory committee
members should be selected based on their disciplinary expertise rather than as representatives of stakeholder
viewpoints. Advisory committee members should not have a financial stake in the outcome of the process or
otherwise have a real or perceived conflict of interest. The external advisory committee should explicitly exclude
representatives of the dietary supplement industry and its trade organizations. It is assumed that the organization
assembling the external advisory committee will use standard practices to identify and avoid other types of
conflict of interest as well.
The composition of the external advisory committee needs to include expertise in critical key disciplines,
but still be small enough to be effective. One approach would be to have the external advisory committee be a
standing committee of about seven persons, with the option to add one or two scientists with special expertise as
needed for the review of individual substances. A second option would be to have a standing committee of five
scientists representing the core disciplines, and the addition of three or four special experts depending on the
nature of the substance and/or the data to be evaluated.
After the external advisory committee is assembled, it will assume responsibility for further refining the
monograph drafted by FDA or the contractor. At this point, a draft monograph should be released, and the public
should be provided with an opportunity to comment on the completeness of the data included, as well as the
strength and relevance to humans of the different types of evidence. Industry and other stakeholders should be
given time during meetings of the external advisory committee to provide input into the process.
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BOX 6–3 ADVISORY COMMITTEE EXPERTISE
The Advisory Committee, either one constituted by FDA or by contracting with a scientifically based,
nonprofit organization, should include individuals with the following expertise:
•
•
•
•
•
•
•
•
•
•
•
•
•
toxicology, preferably with expertise in safety evaluation
pharmacognosy
clinical pharmacology
nutritional science
epidemiology
biostatistics
clinical trials
medicinal chemistry and structure-activity relationships
bioavailability
pharmacokinetics
consumer behavior related to dietary supplement use
public health
ad hoc consultants with expertise in specific fields on an as-needed basis (e.g., specialists needed to
evaluate particular ingredients such as experts on oriental medicine, herbalists, clinicians with relevant
experience).
After reviewing the information collected in the draft monograph and in the public information sessions, the
external advisory committee should revise the draft monograph as needed to create as complete a picture of the
scientific information available on safety as possible within the resources available to FDA. The advisory
committee should evaluate this information and reach conclusions where possible, describing what is known
about the safety of the ingredient based on the weight of the scientific evidence. The conclusions should describe
• the relevance of the evidence;
• the seriousness of the potential harm suggested by the evidence; and
• the quality and quantity of the evidence.
The advisory committee's conclusions should include comments about the risks and hazards that may be
associated with use by the general population, as well as risks that may be particular to subgroups of the
population. As much as possible, the advisory committee should describe how its conclusions may be dependent
on how the ingredient is used—that is, the dose, manner, and form.
The advisory committee may conclude that there is little or no substantial evidence within the available
information to suspect a hazard to the public when the ingredient is used at the recommended levels on the label,
or at levels that might reasonably be expected. If current use does not demonstrate a hazard, the advisory
committee may decide to comment on if it is possible to foresee whether a significant increase in consumption
would constitute a hazard. If there is not enough information available to conduct a scientific evaluation of the
safety of the dietary supplement, the advisory committee should indicate this. All conclusions should also be
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accompanied by a description of additional research needed. If uncertainties exist that could be addressed by
further study, the advisory committee should identify in detail what the uncertainties are and what types of
studies could help resolve them.
After the advisory committee's conclusions are shared with FDA, the revised monograph and the advisory
committee's conclusions should be posted on FDA's website. One of the important components of the Dietary
Supplement Health and Education Act of 1994 was that the public should be educated about dietary
supplements. FDA thus has a responsibility to educate consumers about the safety of supplement ingredients,
and the public availability of the revised monographs can be an important aspect of the educational process. The
monographs will provide the public with a reputable summary of the available information and scientific
uncertainties about the inherent safety of the supplement ingredient. Importantly, public access to information
from an advisory committee that is free of direct conflicts of interest will add to the quality and quantity of the
available scientific literature.
An added benefit of making monographs easily available to the public is that industry and publicly funded
scientists may choose to conduct studies that address the concerns raised, increasing the knowledge base of
dietary supplement safety. The general public, as well as industry, pharmacists, health care providers, and
distributors will benefit from the publicly available information and individually can decide whether to use, sell,
or recommend the dietary supplement ingredient, even if FDA decides not to take action.
The monographs developed should not be considered static documents. New information should be added
as it becomes available, and an organized process for adding information should be developed. The process
should also include periodic reviews of monographs to determine if additional external reviews are appropriate.
OVERSIGHT OF MONOGRAPH PREPARATION AND REVIEW
Preparation of Draft Monographs
Collecting descriptive and safety information and organizing and summarizing the information into a draft
safety monograph will require significant expertise and resources. Time and other resources required to complete
the draft monographs are likely to vary, as some draft monographs will be extensive and others will be brief,
depending largely on the amount of relative safety information available for the dietary supplement ingredient
being considered. FDA may choose to prepare monographs internally, or it may choose to contract the work out
to organizations, individuals, or both.
There are a number of academic, nonprofit, and for-profit organizations that have the resident expertise and
administrative abilities to prepare monographs as directed by FDA. It is also possible that unbiased individuals
without conflicts of interest could be identified to prepare draft monographs, but organizations are probably a
more objective resource for monograph preparation. In addition, if FDA aims to obtain as many monographs as
possible in the shortest timeframe acceptable, organizations rather than individuals may be more qualified.
The extent of time and effort devoted to preparation of monographs on dietary supplement ingredients will
depend on FDA's prioritization of need. FDA could screen, set priorities, and then develop a complete list of
substances warranting monographs first. Alternatively, FDA could retain one or more individuals or groups to
develop monographs and determine the need for individual monographs on an ongoing basis as priority setting
proceeds or as new needs emerge. The former approach may be more cost effective to implement, given that the
latter
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approach might not provide continuity in workload. However, preparing a list of priority substances to be
monographed under contract will require more resources up front and will be dependent on information available
at the time the list is prepared.
Assuming that draft monographs are prepared under contract, FDA may choose to directly monitor the
monograph preparation done by individuals. Otherwise, it may choose to contract with an outside organization to
administer and manage the monograph preparation process. The first approach involves direct control of the
activities of the individuals preparing the monographs by FDA staff monitoring the contract deliverables, while
the second delegates that responsibility to an outside organization.
Depending upon the type and expertise of the contracting organization, it is possible that additional aspects
of the critical evaluation step could be carried out by the organization. The critical safety evaluation process
described in this chapter includes provision for additional data and input to be provided by industry and other
stakeholders. Typically, this input process involves announcement of the request for data and information,
submission of written materials, and oral testimony at a public meeting. If FDA contracts with organizations that
do not have the capability to conduct such activities, FDA would have to undertake these information gathering
and collation activities itself for the contracting organization. However, if FDA contracts with an external
scientifically based, nonprofit organization, this organization could administer and manage the monograph
preparation process with the assistance of one or more individuals whose sole responsibility would be
monograph preparation. This organization would conduct the public information gathering process, and monitor
the preparation, publication, and dissemination of the draft monographs for review and submittal to FDA.
Additional advantages of this approach include relieving FDA of administrative management and increased
public assurance that the draft monograph is as complete and as objective as possible. In addition, if FDA first
develops an extensive list of substances warranting monographs, contracting with an external scientific
organization would be an efficient method of managing the entire process and the simultaneous development of
several monographs; such processes have been employed in the past.
The disadvantages of this tiered approach include the necessity for fiscal resources from FDA to support the
ongoing administrative and monograph preparation processes. However, the absence of direct governmental
control of the information gathering and expert evaluation process suggests this latter approach should be given
serious consideration.
Management of the External Advisory Committee
As discussed above, FDA should consider each draft monograph developed either internally or by a
scientifically based organization and decide if additional expert opinion would be helpful in evaluating the
evidence. Therefore, in addition to determining who will be responsible for preparing draft monographs, FDA
will also need to decide whether to establish or contract to have established an external advisory committee to
develop conclusions and research needs and provide further input on the draft monograph.
If an external, as opposed to internal (i.e., made up of FDA scientists with appropriate backgrounds),
advisory committee is established, several options for administrative management of the external advisory
committee could be considered. One option is for the external advisory committee to be a standing subcommittee
of the Center for Food Safety and Applied Nutrition's existing Dietary Supplements Committee, which is itself a
subcommittee of the Food Advisory Committee. As such, external advisory committee members would be aware
of ongoing issues of
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wider interest regarding dietary supplements. However, the affiliations of persons on the Dietary Supplements
Committee might make this approach difficult to carry out while assembling a group as free as possible from
conflicts of interest. Time commitment might be a consideration in whether to include one or more members of
the Dietary Supplement Committee. To be effective over time, the external advisory committee members should
anticipate tenure of at least three years with at least four meetings per year. Administratively, the external
advisory committee might have a workload analogous to the former Life Sciences Research Office Select
Committee on GRAS Substances or a National Institutes of Health Study Section.
Another option is for the external advisory committee to be either a free-standing entity or to be an activity
conducted by an external scientific organization under contract to FDA. If the external advisory committee were
a free-standing entity that is disassociated from the monograph preparation process, there would be an increased
burden of cost for its management. If the external advisory committee management and the monograph
preparation are subsumed under one contract with a nonprofit, scientifically based organization, then
administration and management might be less costly and have greater continuity. One advantage of separating
management of the external advisory committee from FDA is that this approach would provide greater assurance
to the public of the external advisory committee's independence and objectivity. The proposed process regarding
development of the draft monograph and public input does not include consensus conclusions, but if FDA
determines that consensus conclusions about the safety of dietary supplement ingredients are necessary, then
there are additional advantages to contracting with an outside organization to facilitate the development of them.
In this case, it would be necessary to identify an organization that has adequately experienced and
knowledgeable scientific and administrative staff to manage both the monograph preparation process and the
conduct of objective scientific evaluations. A limited number of scientific organizations have the capabilities to
meet the administrative, managerial, and scientific requirements required for this approach.
SUMMARY
In summary, this chapter outlines a system for preparing monographs and conducting reviews of dietary
supplement ingredient safety. FDA or a contractor of FDA would prepare the initial draft monograph that is a
collection and review of available safety information. FDA would then determine whether additional input to the
draft monograph would be helpful. If the data are not sufficiently clear for FDA to make a decision about
whether to take action, or for any other reason, an advisory committee could be requested to review the
information. An external advisory committee could be established to accomplish this task. The external advisory
committee would review the draft monograph, determine if additional information should be collected, and hold
sessions for input from the public. It would then modify the draft monograph as appropriate and make
conclusions based on the evidence. The revised monograph, along with the external advisory committee
conclusions, would be made public in an easily accessible format.
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7
Attributes and Limitations of the Proposed Framework
The previous chapters propose a framework for screening/flagging, priority setting, and conducting a full
safety evaluation for dietary supplement ingredients. This framework was drafted after considering systems used
by other organizations for reviewing the safety and effectiveness of dietary supplement ingredients, and after
considering frameworks that have been established to evaluate the safety of other types of substances, as
described in Chapter 2.
ATTRIBUTES OF THE PROPOSED FRAMEWORK
There are a number of attributes of the proposed framework, and there are also a few limitations. This
framework integrates the variety of available evidence about safety, balancing the value of different types of
evidence and also integrating prevalence of use information to enhance the public health impact of the process.
Using the framework, FDA can be both proactive and reactive, as well as provide an open and transparent
process helpful to the general public and industry.
First and foremost, it is important to note that this framework focuses on how to consider the safety of
dietary supplement ingredients rather than offering guidance on how to consider their benefits and role in health.
This was a key point of the request to the Institute of Medicine from FDA, as is appropriate since dietary
supplements are regulated as foods that are assumed to be safe, rather than as drugs requiring a risk-benefit
analysis.
As mentioned above, a strength of the proposed framework is that it incorporates several different types of
data that may be available, providing a mechanism to evaluate the totality of the available data—not just relying
on one type, such as human data. Utilizing the diverse types of data available (i.e., the different “factors”) is
especially important because the extent of the types of data available are vastly different from one dietary
supplement ingredient to another. Since FDA has no authority to require specific types of studies or data in
advance of marketing, it is not possible to have available for safety review the same types of information
regardless of the ingredient. Thus the integrative approach proposed is more useful than centering a framework
on one type of data in establishing priorities and subsequently reviewing safety.
A somewhat distinct aspect of this framework, compared to the approaches taken by other organizations, is
that it reflects a public health perspective that a supplement ingredient used by more individuals warrants greater
attention, given similar safety concerns. The framework
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reflects this perspective by integrating estimates of prevalence of use with the available safety information as
part of the priority-setting step.
In addition to providing a method for integrating various types of information, the framework is also
practical in that it allows FDA to be both proactive and reactive. The screening/flagging and priority-setting
steps are reactive in nature, providing a mechanism for FDA to integrate new safety concerns into the existing
priority scheme. The priority-setting mechanism can be initiated with limited information, but as additional
resources are devoted to proactively searching for data, the level of concern characterized by the priority group
to which a dietary supplement ingredient is assigned becomes increasingly accurate. As additional information
about flagged ingredients becomes available, the information is used to update “scores” of dietary supplement
ingredients that have not yet reached Step Three (the critical safety evaluation), easily updating and thus revising
the ingredient's priority ranking. For example, it is easy to envision that a new clinical study may report serious
adverse events for an ingredient, changing its score for human data from an NAD (no appropriate data) to a 3.
The priority ranking of this ingredient relative to the others is easily adjusted to reflect this new information.
The practical nature of the framework is also reflected in the fact that it allows FDA to score each
ingredient one factor at a time. Relative priorities can be set without having to simultaneously consider the entire
array of each ingredient's safety concerns.
The critical safety evaluation step is designed to be as open and transparent as possible, so a mechanism for
the public and the relevant industry to provide data and other input is provided. Keeping the activity open and
transparent also allows the general public to be able to access safety conclusions made by scientists devoid of
conflicts of interest. For this reason, the framework stresses the value of making safety reviews readily available
to the public.
LIMITATIONS OF THE PROPOSED FRAMEWORK
In addition to the framework's attributes outlined above, there are also limitations inherent to the
framework. By definition, the framework cannot be used to consider the possible benefits of consuming dietary
supplement ingredients. Another limitation is that, as with any evaluation of dietary supplement ingredients
under the current regulatory scheme, the framework's evaluation of safety depends on publicly available data or
data voluntarily made available by industry and other groups. Another limitation of this framework is that a
major component of it is human data, which unfortunately can be highly variable in quality and quantity.
The framework, especially through the priority-setting scoring process, seeks to evaluate explicitly the
different components of the data—considering the evidence or possible risk, seriousness of harm, the hierarchy
of data types, and the potential public health impact as distinct variables. This approach attempts to guide
judgments made at the screening/flagging and priority-setting steps, but judgment of safety is in the end a
subjective determination dependent upon expert interpretation of the totality of evidence.
The use of expert judgment via an external advisory committee may itself be another limitation, in that the
number of qualified experts not associated with industry or the regulatory agency may be limited.
An additional limitation of the framework is the extent to which evaluation of the safety of any combination
of dietary supplement ingredients can be conducted when the review is limited to available data. In the absence
of having the authority to require manufacturers to present specific evidence of safety, the burden of conducting
studies to ascertain adverse effects is
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placed on FDA, which has limited resources compared to the number of the dietary supplements currently
marketed.
SUMMARY
While the framework approach outlined here is not based entirely on empirical data, it should provide a
mechanism for FDA to accomplish its goal of using a science-based approach to set priorities for evaluating the
safety of dietary supplement ingredients given its available resources and the legislative authority under which it
regulates the industry.
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8
Dietary Supplement Ingredients Selected for Prototype Safety
Monographs
The second phase of the Food and Drug Administration's (FDA) charge to the Committee on the
Framework for Evaluating the Safety of Dietary Supplements is to, after proposing a framework for the safety
evaluation of dietary supplement ingredients, develop at least six monographs as prototypes for the system
outlined in the framework. Based on this experience and on comments received by industry and other
stakeholders about the proposed process, the framework will be revised and included in a final report along with
the prototype monographs.
These monographs are referred to as “prototypes” for several reasons. Because the six monographs are
simultaneously being prepared within the timelines of the overall IOM project, the information collected is not
expected to be as complete as what might be collected if FDA or another organization was specifically charged
to undertake only the monograph generation. For example, the timeline of this project requires that industry and
other stakeholders volunteer data within one month after the time the dietary supplement ingredients under
consideration are announced. The sources of and process for systematically collecting information is also being
considered during this process and is likely to be refined with experience.
CHOICE OF INGREDIENTS FOR PROTOTYPE MONOGRAPH DEVELOPMENT
The six supplement ingredients selected by the committee as the subject of prototype monographs are (in no
particular order other than alphabetical): chaparral, chromium picolinate, glucosamine, melatonin, saw palmetto,
and shark cartilage.
These six ingredients were selected to fulfill several criteria. One criterion, for example, is that the
selections include at least one botanical, one vitamin or mineral, one animal product, and one hormonal product.
Another criterion is that the selected ingredients include substances for which a range of different types of
available information and a range in the quality of available information are anticipated. Finally, selected
ingredients should not be undergoing safety research by committee members so as to possibly bias the review or
interpretation.
The ingredients chosen for monograph development would be expected to be flagged in the screening/
flagging step and would therefore enter the priority-setting step. The selected ingredients would not necessarily
be expected to be at the top of the priority list of all flagged ingredients, but a few are. The selected ingredients
might have been flagged in Step One for a
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variety of reasons, many of which fall under “other concerns.” Chaparral has raised safety concerns from
authoritative sources. In 1992 FDA issued a press release warning of a potential relationship between its use and
liver toxicity (FDA, 1992), the MedWatch System has documented several adverse event reports (CFSAN, 1993;
OSN, 2002), and the American Herbal Products Association's Botanical Safety Handbook (McGuffin et al.,
1997) noted that Health Canada did not allow chaparral as an orally-administered, nonmedicinal ingredient.
Possible liver problems were also mentioned in several other secondary sources of information (Foster and Tyler,
1999; NMCD, 2002). Glucosamine was flagged because secondary sources raised concerns about its use by
persons with diabetes (Hendler and Rorvik, 2001, NMCD, 2002). Melatonin was flagged because of serious
adverse events reported to the MedWatch system (OSN, 2002). Shark cartilage was flagged because the
Committee was aware of a case report of hepatitis following ingestion (Ashar and Vargo, 1996), and it was
selected to allow the committee to consider an animal product at this phase of the review. Saw palmetto was
flagged because of two serious cardiac events reported to the Medwatch system (OSN, 2002). Finally, chromium
picolinate was flagged because secondary sources mentioned that its use has been reported in renal toxicity cases
(Hendler and Rorvik, 2001), and because secondary sources discussed its purported effect on insulin regulation
and use by persons with diabetes (NMCD, 2002).
NEXT STEP
The next step of this IOM project is to collect safety-related data on these six ingredients from industry,
consumer groups, and other interested parties, as described in Chapter 6. These data should be provided to IOM
no later than one month after the proposed framework is released for public comment. The draft monographs
summarizing the collected data and other available data will then be released for additional public input, with
comments due in a short period of time.
Industry representatives, consumer protection advocates, and other stakeholder representatives will be
invited to provide oral and written input at open sessions to be held in Washington, D.C. It is expected that these
open sessions will be held in August and September 2002. The committee, with input from working groups and
consultants on each ingredient, will release prototype monographs with conclusions about safety concerns and
further research needed as part of the final revised framework report.
REFERENCES
Ashar B, Vargo E. 1996. Shark cartilage-induced hepatitis. Ann Intern Med 125:780–781.
CFSAN (Center for Food Safety and Applied Nutrition). 1993. Illnesses and Injuries Associated with the Use of Selected Dietary
Supplements. Online. Food and Drug Administration. Available at http://vm.cfsan.fda.gov/~dms/ds-ill.html. Accessed July 9, 2002.
FDA (Food and Drug Administration). 1992. Chapparal Warning. P92–38. December 10. Press Release.
Foster S, Tyler VE. 1999. Tyler's Honest Herbal. A Sensible Guide to the Use of Herbs and Related Remedies. 4th ed. New York: Haworth
Herbal Press.
Hendler SS, Rorvik D, eds. 2001. Physician's Desk Reference for Nutritional Supplements. Montvale, NJ: Thomson Medical Economics
Company.
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CRC Press.
NMCD (Natural Medicines Comprehensive Database). 2002. Products. Online. Available at http://www.naturaldatabase.com/products.asp?
1tr=c. Accessed July 10, 2002.
OSN (Office of Special Nutritionals). 2002. The Special Nutritionals Adverse Event Monitoring System. Online. Center for Food Safety and
Applied Nutrition, Food and Drug Administration. Available at http://www.cfsan.fda.gov/~dms/aems.html. Accessed July 11, 2002.
APPENDIX A
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Appendix A
Other Approaches to Considering the Safety of Dietary
Supplements
The following text provides an overview of the different approaches taken by other groups to consider the
safety of dietary supplements. Please note that the summaries reflect information published or provided by the
organizations involved, and do not reflect judgments or endorsements of the committee.
AGENCY FOR HEALTHCARE RESEARCH AND QUALITY
The Agency for Healthcare Research and Quality (AHRQ) of the U.S. Department of Health and Human
Services aims to sponsor, conduct, and disseminate research to improve the quality and effectiveness of health
care. Other federal agencies, private sector agencies, and Congress have asked AHRQ to review and evaluate the
scientific information on specified topics to be used as the basis for clinical guidelines, performance measures,
and other quality improvement tools. This AHRQ program is referred to as the Evidence-based Practice Centers,
and it has produced “evidence reports” requested by other federal agencies on the effectiveness and safety of a
limited number of dietary supplements. The San Antonio Evidence-based Practice Center (EPC) at the
University of Texas Health Sciences Center, working under contract to AHRQ, has completed reports on garlic
and milk thistle. In addition, the Southern California Evidence-based Practice Center/RAND is developing an
evidence report on the clinical efficacy and side effects of ephedra.
The EPC evidence reports are based on a systematic analysis of the relevant scientific data. Other groups,
such as the well-known Cochrane Collaboration, prepare and maintain similar evidence-based reviews. These
reviews are based on a weighting/ranking methodology and are dependent on judgments that are based on welldefined criteria.
The first step of an AHRQ review is to identify relevant citations through what is intended to be an
exhaustive search of the literature in a variety of electronic databases. Additional citations are identified from
bibliographies, manufacturers, and technical experts. Both English and non-English references are included in
the search. In general, only published full articles are used, but additional unpublished information provided by
authors of published studies are also included.
Independent reviewers on the EPC staff read the titles and abstracts of all the identified citations and
exclude those citations that do not meet certain selection criteria on types of participants, interventions, control
groups, outcomes, and study designs. To assess adverse
APPENDIX A
107
clinical events, all types of human studies are used (e.g., randomized controlled trials, prospective trials, casecontrol, and cohort studies). Data are abstracted from the literature and analyzed by independent reviewers with
clinical and methodological expertise. The analysis includes an assessment of the internal validity and quality of
the studies. The data analysis includes generation of evidence tables, graphical summaries, statistical tests, and
meta-analyses. The results and conclusions of the analyses are summarized in an evidence report that contains
conclusions on the current knowledge on the efficacy and adverse effects of the substance and provides
recommendations for future research. Reports are available on the AHRQ website (http://ahrq.gov).
Nominations for clinical topics to be reviewed by an Evidence-based Practice Center are solicited through
notices in the Federal Register. Topics must meet specific selection criteria including high incidence;
significance for the needs of Medicare, Medicaid, or other federal health programs; high cost; controversy about
effectiveness; and availability of scientific data. Based on this process, the dietary supplements milk thistle and
garlic, in addition to over 70 other nondietary supplement topics, have been reviewed (AHRQ, 2002).
U.S. PHARMACOPEIA-NATIONAL FORMULARY
The U.S. Pharmacopeia-National Formulary (USP-NF) develops and provides standards of identity,
strength, quality, purity, packaging, and labeling of drugs sold in the United States in the form of standards
monographs; these standards monographs do not consider the inherent safety of the substance. The USP
standards are recognized by Congress in the Federal Food, Drug, and Cosmetic Act of 1938 (21 U.S.C. § 321 et
seq.) as the official compendium of the United States, making its established standards for drugs essentially
similar to federal regulations (USP, 2002a). From its first publication in 1820, the USP contained monographs
for hundreds of botanicals; however, most of them were removed by the end of the 1930s due to the changes in
medical practices and the arrival of synthetic organic medicinal compounds in the U.S. marketplace. In 1990, in
response to a USP Convention Resolution, the USP Committee of Revision, an independent body of elected
scientific experts representing industry, academia, and government agencies, established public standards for
vitamins, minerals, and their combination products. These standards monographs, along with general chapters
that include manufacturing practices for nutritional supplements, were grouped together and published within a
separate section of the USP called Nutritional Supplements.
In 1995, after passage of the Dietary Supplement Health and Education Act (DSHEA), the USP
Convention, in recognition of the resurgence in the use of botanicals by the American public, adopted a
resolution that encouraged the USP Committee of Revision to establish public standards for botanical dietary
supplements. In response to the Convention resolution, the USP Committee of Revision generated a list of
approximately 20 widely used botanicals for public standards monographs. Criteria for identification of these
botanicals included lack of safety risk, extent of use by consumers, interest from regulatory agencies, positive
assessment by recognized pharmacognosists, and the ability of the botanical to meet typical requirements for
USP monographs. History of traditional use and pharmacological action were also considered. Standards
monographs are not developed for botanicals that the USP believes may be associated with a significant safety
risk (USP, 2000a, 2002b).
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Once a botanical has been approved for inclusion in the USP or NF13, analytical methods are requested
from several manufacturers and reviewed by the USP Expert Committee relating to dietary supplements. Before
official adoption into USP-NF, public comment on proposed standards is generated by publicizing them in
Pharmacopoeia Forum (Personal communication, V.S.Srinivasan, U.S. Pharmacopeia, February 11, 2001).
U.S. PHARMACOPEIA DIETARY SUPPLEMENT VERIFICATION PROGRAM
Distinct from its monograph development program, the USP launched its Dietary Supplement Verification
Program (DSVP) in October 2001. This program's goal is to ensure that dietary supplement products contain the
ingredients stated on the product label (Personal communication, V.S.Srinivasan, U.S. Pharmacopeia, February
11, 2001).
Dietary supplement manufacturers who pay to participate in the program will have their products reviewed
by USP, and if the product meets the DSVP program requirements, the product will be granted a USP
certification mark. This mark is intended to signify that the product contains the ingredients stated on the label in
the declared amount and strength, meets stringent standards for product purity, meets specified limits on known
contaminants, and has been manufactured under good manufacturing practices according to the USP-NF General
Chapter on Manufacturing Practices for Nutritional Supplements and the FDA's Advance Notice of Proposed
Rulemaking for good manufacturing practices (USP, 2001). Importantly, the DSVP certification mark is not
intended to imply safety or efficacy of dietary supplement ingredients.
AMERICAN HERBAL PHARMACOPOEIA
The American Herbal Pharmacopoeia (AHP), a nonprofit organization, develops monographs on the
quality, effectiveness, and safety of botanical medicines commonly used in the United States (Blumenthal,
1997). The monographs include botanicals with origins in Ayurvedic, Chinese, and Western traditions and
includes information from both traditional and scientific sources (CRN, 1998; Upton, 1999). The monographs
are intended to provide consumers, health professionals, and botanical manufacturers with the knowledge
required for using and manufacturing botanical products safely and effectively, and to provide regulatory bodies
and researchers with guidance for integrating botanical products into the health care system (AHP, 2001).
Selection of a botanical for monograph development can be made by three methods. A Prioritization
Committee consisting of professional herbalists, botanical industry representatives, and herbal educators
produces a list of priority botanicals based on the extent of their use or the unique value of the botanical. A
second method is through monograph sponsorship. Because AHP seeks funding and technical support for
development of monographs from interested organizations or companies, a sponsored botanical may be given
higher priority than was assigned by the Prioritization Committee (AHP, 2001). Thirdly, AHP considers what
other groups have done. If there is an existing monograph of a botanical on the prioritization list, AHP may use,
with permission, relevant sections of that monograph as a starting point for its own monograph development
(AHP, 2001).
13 Whether a botanical monograph is admitted into the USP or its companion guide, the NF, currently depends on its
approval status, as determined by the USP. If the botanical has an FDA- or USP-approved use, then standards are developed
for it and it is published in the USP; otherwise, the standards for the botanical are published in the NF.
APPENDIX A
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According to AHP, the first step in the development of an AHP monograph is a search of the primary
literature. Primary literature is preferred, but secondary literature such as review articles may be used if
considered acceptable or necessary. The search is not limited to English-language references. To address the
safety of the botanical, a review of the toxicological literature is done and includes data on acute and chronic
toxicity; use during pregnancy, lactation, fetal development, and driving; mutagenicity; teratogenicity; and
carcinogenicity. All reported side effects, contraindications, and negative interactions are reviewed (AHP, 2001).
Next, each section of the monograph is assigned to a writer with expertise in that section area, and the
writer is provided with the results of the literature search. Once the sections are drafted, the AHP editor and at
least one other expert in the specific field reviews them. All the sections are then incorporated into an initial
monograph draft. This draft is then circulated to a peer-review committee of botanists, chemists, herbalists,
pharmacists, pharmacologists, pharmacognosists, and physicians (AHP, 2001). Reviewer comments are
incorporated into the draft and the initial authors review and approve their sections. Before it is finalized for
publication, the monograph is reviewed by an expert of either the botanical under review or the physiological
system that the botanical affects (AHP, 2001).
AMERICAN HERBAL PRODUCTS ASSOCIATION
The American Herbal Products Association (AHPA) is a national trade association for the botanical
products industry. In response to passage of DSHEA, AHPA convened a special subcommittee of their Standards
Committee to address the need for a comprehensive review of safety data for botanical ingredients sold in North
America. According to AHP A, the goal of this committee, which consisted of three natural product scientists
and practicing herbalists, was to critically evaluate safety and categorize botanicals based on safety. These
evaluations are published as The Botanical Safety Handbook (McGuffin et al., 1997).
The committee reviewed botanicals that were on the market in the United States, identified primarily by
reviewing Herbs of Commerce, another AHPA publication (Foster et al., 1992). After identifying which
botanicals to include, AHPA reported that its committee reviewed the available scientific literature for data on
human and animal toxicity, traditional use, regulatory status in numerous countries, and current usage of herbs in
the United States, China, India, Europe, and Australia. Notably, the committee also relied on its own and others'
expertise and clinical experience for the evaluations.
There was no formal weighting of the data used for the evaluations; however, there were some exclusionary
criteria. The monographs did not include the following data, conditions, or related products: excessive
consumption, safety or toxicity concerns based on isolated constituents, toxicity data based solely on intravenous
or intraperitoneal administration, traditional Chinese and Ayurvedic contraindications, gastrointestinal
disturbances, potential drug interactions, idiosyncratic reactions in sensitive individuals, allergic reactions,
contact dermatitis, well-known toxic plants that are not found in products on the market, homeopathic herbal
preparations, essential oils, botanical products to which chemically-defined active substances had been added, or
environmental factors, additives or contaminants.
The AHPA review committee followed guidance from the World Health Organization's (WHO) Programme
on Traditional Medicines (WHO, 1991), which states that regulatory action is not necessary for traditionally used
products that have not been shown to be harmful unless new evidence necessitates a risk-benefit assessment. The
AHPA safety classification was based on an assumption of rational, informed use of botanicals and the
committee stated that it
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carefully considered the intended use of the substance within the historical context of that use (McGuffin et al.,
1997). As listed in the exclusionary criteria above, the committee reported that it did not extrapolate toxicity data
of isolated constituents and did not use data from studies that had excessive or irresponsible consumption
patterns (McGuffin et al., 1997).
Once the committee reviewed all available information, the botanicals were assigned to one of four safety
classes. Class 1 are botanicals that the AHPA committee believes can be used safely when used appropriately.
Class 2 are botanicals for which certain restrictions apply (see subclasses) unless otherwise directed by an expert
qualified in the use of the substance. Class 2a are botanicals only to be used externally. Class 2b are botanicals
not to be used during pregnancy. Class 2c are botanicals not to be used while lactating. Class 2d are botanicals
for which other use restrictions have been specified in the monograph. Class 3 are botanicals for which
significant data exist to recommend special labeling: “to be used only under the supervision of an expert
qualified in the appropriate use of this substance.” Class 4 are botanicals for which the AHPC committee found
insufficient data for classification.
NATURAL MEDICINES COMPREHENSIVE DATABASE
The publishers of Pharmacist's Letter and Prescriber‘s Letter created the Natural Medicines
Comprehensive Database (NMCD) that is available online and in printed version (NMCD, 2002). The stated
goal is to bring together in one place the consensus of the available data on natural medicines so that
practitioners do not need to search multiple sources to find scientifically reliable and clinically practical
information on botanical medicines and supplements for their patients. NMCD reports that it provides an
assessment of the available data regarding safety and effectiveness of each natural medicine reviewed and that it
covers nearly every natural medicine on the market in North America (NMCD, 2002). New product reviews are
prioritized based on market saturation and requests by health professionals (Personal communication, P.Gregory,
NMCD, February 21, 2002).
For each product that is reviewed, a research team of pharmacists, physicians, and pharmacologists begins
the process with a literature search. Initially, when the database was first being developed, the research team
consulted reference textbooks such as the Commission E Report, the Physician's Desk Reference, and AHPA's
Botanical Safety Handbook for their evaluation of the literature. However, the research team soon turned to the
primary literature using electronic databases such as Medline and Toxline to find the pertinent literature.
For the most part, the research team limited their search to English-language references. However, nonEnglish articles of special significance are also included. For the safety evaluation, the team relied mainly on
human data; animal data were rarely used (Personal communication, P.Gregory, NMCD, February 21, 2002).
After completion of the literature review, the information is evaluated and a consensus on any relevant
issues is reached by the research team (NMCD, 2002), and then a single author drafts the reviews. The draft is
then sent out for review to two or three pharmacists and physicians who were not on the research team. After this
review, final drafts are added to the database (Personal communication, P.Gregory, NMCD, February 21, 2002).
Each product is rated according to specific criteria as: likely safe., possibly safe, possibly unsafe, likely
unsafe, or unsafe. Natural products that are rated likely safe are those for which there is general agreement
among reliable references that the product is safe when used appropriately or those for which a governmental
body has approved their use. A product is rated possibly safe if the reputable references suggest that the product
might be safe when used
APPENDIX A
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appropriately or there are human studies that report no serious adverse effects. A rating of possibly unsafe
requires that there is some data suggesting product use might be unsafe. Likely unsafe indicates agreement
among reputable references that the product can be harmful or there are reliable reports of harm to product users.
A rating of unsafe is based on finding general agreement among reliable references that the product should not
be used, reliable reports of clinically significant harm to product users, or safety warnings issued by a reliable
agency for the product. Special mention is made if use during pregnancy, lactation, or in children presents
special concerns. Natural products that have different uses (e.g., oral versus topical use) may receive more than
one rating (NMCD, 2002).
WORLD HEALTH ORGANIZATION
WHO has developed international specifications for medicinal plants that are the most widely used in an
effort fill the need for current, authoritative information on their safety and efficacy. WHO has published the first
volume of 28 monographs on selected medicinal plants (WHO, 1999). A second volume is in press, and a third
volume has been approved and is in preparation. The medicinal plants and products in each volume of
monographs were selected by a WHO advisory group based on the extent of each plant's use and importance
throughout the world and on the sufficiency of the data available to evaluate safety and efficacy. The goal is to
include information on safety, effectiveness, and quality control of botanical medicines. The monographs present
descriptive information, purity tests, chemical constituents, medicinal uses, clinical studies, pharmacology,
contraindications, warnings, precautions, adverse reactions, and posology.14
Each monograph was drafted under the direction of a team of experts in botanical medicines and medicinal
plants. Information for the monographs was collected from a review of the literature, bibliographies, review
articles, pharmacopoeias from several countries, reference books, and the NAPRALERT database. Once drafted,
the monographs were reviewed by a large number of additional experts throughout the world with expertise in
traditional medicine, drug regulation, drug evaluation, and pharmaceutical science. Finally, WHO convened a
Consultation on Selected Medicinal Plants that consisted of 16 experts in medicinal plants and drug regulation to
approve, modify, or reject the proposed monographs. WHO plans to periodically supplement and update the
monographs as new data are made available (WHO, 1999).
COMMISSION E
In 1978 the Second Medicines Act in the Republic of Germany went into effect, requiring a scientific
review of all medicines in the pharmaceutical market including conventional drugs and medicinal plants and
phytomedicines. This resulted in the formation of a series of scientific commissions. Commission E was
established by the German Minister of Health to review botanical drugs and preparations from medicinal plants.
This 24-member committee was made up of physicians, pharmacists, nonmedical practitioners, pharmacologists,
toxicologists, and biostatisticians (Blumenthal, 1998). According to the Commission E member consulted, at
least 60 percent of the commission members had practical experience with phytomedicines (Personal
communication, H.Schilcher, Commission E, March 19, 2002). The Commission completed its monograph work
in 1994; however, it has met since 1994 to review drug registrations
14
From the Greek, posos, (how much), representing the science or doctrine of dosing.
APPENDIX A
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(Blumenthal, 1997). The monographs produced by Commission E have been compiled and published in English
by the American Botanical Council (Blumenthal, 1998). This publication and input from Commission E also
describes the process used by Commission E, in addition to input from a member of the Commission E as the
basis for this summary (Personal communication, H.Schilcher, Commission E, March 19, 2002).
The stated objective of Commission E was to ensure that approved botanicals were reasonably safe when
used according to the product label instructions and to remove unapproved botanicals from the market even if
they only posed minor safety risks (Blumenthal, 1998). Commission E reviewed 378 botanicals used in German
folk medicine for both safety and effectiveness (Blumenthal, 1997; Personal communication, H.Schilcher,
Commission E, March 19, 2002). It was the manufacturer's responsibility to provide proof of quality
(Blumenthal, 1998). Safety and effectiveness were assessed using the published scientific literature.
Approximately 100 to 200 worldwide references were consulted for each botanical (Personal communication,
H.Schilcher, Commission E, March 19, 2002).
The Commission considered data on traditional use, chemical composition, pharmacology, and toxicology
and used data from clinical studies, in vitro and in vivo studies, field studies, epidemiological studies, case
reports, and unpublished proprietary data submitted by manufacturers that included chemical, lexicological,
pharmacological, and clinical testing data. The Commission also reviewed summaries produced by Kooperation
Phytopharmaka (an umbrella organization of about 120 pharmaceutical manufacturers). These Kooperation
Phytopharmaka summaries were based on literature reviews and clinical experience, but did not contain any
recommendations about the product under review (Blumenthal, 1998).
According to the American Botanical Council's description, controlled clinical studies appear to have been
considered the most useful type of data (Blumenthal, 1998). If no controlled studies were available, safety was
evaluated based on other types of data such as well-documented review articles, older clinical trials, and welldocumented knowledge of traditional usage. Blumenthal (1998) indicates that Commission E did not accept longterm therapeutic or traditional use as sufficient evidence of safety without additional data, and that field and case
studies were only used when they had been evaluated according to scientific standards.
Once the Commission finished drafting a monograph for a botanical medicine, it was published and
comments were solicited from scientists and other experts. The Commission then prepared a final draft of the
monograph. Notably, the monographs do not include references. An unpublished justification with relevant
references for the monographs are kept; however, these justifications cannot be accessed except in cases of legal
disputes (Blumenthal, 1998).
Each substance was assigned one of three approval ratings: (1) positive (approved), (2) negative
(unapproved), or (3) negative-null (unapproved). Positive/approved substances were considered reasonably safe
when used according to the dosage, contraindications, and other warnings specified in the monograph. If safety
concerns outweighed the potential benefits of a substance, the monograph was assigned a negative (unapproved
rating). No dosage recommendations were provided for substances assigned a negative rating, and the intent of
the Commission was the immediate withdrawal of these substances from the market. If no risk was found, but
also no substantiated efficacy, the substance was designated as negative-null (unapproved). If manufacturers
could later document the efficacy of such substances, the products could be approved; however, no new
monographs would be produced (Blumenthal, 1998).
APPENDIX A
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HEALTH CANADA NATURAL HEALTH PRODUCTS DIRECTORATE
In Canada vitamin and mineral supplements, herbal products, homeopathic preparations, and traditional
Chinese, Ayurvedic, and native North American medicines are considered to be natural health products (NHPs).
At present, there are no specific regulations for NHPs—they are regulated as either foods or drugs depending
upon the active ingredient, the form of the product labeling, and the presence or absence of claims.
In 1997, in response to growing concerns about access to NHPs, the Minister of Health asked the Canadian
House of Commons Standing Committee on Health to conduct a full review of how NHPs were regulated in
Canada and how the government could better provide Canadians with the safety, quality, and freedom of choice
that they were seeking. Following extensive consultation, the Standing Committee issued its report in November
1998. The report contained 53 recommendations, including the establishment of a new regulatory authority
specifically for the regulation of NHPs.
In March 1999 the government accepted all of the recommendations of the Standing Committee and
announced the creation of the Office of Natural Health Products (now the Natural Health Products Directorate)
within Health Canada (the federal department of health) as the authority charged with developing and
maintaining a regulatory framework for NHPs. An Expert Advisory Committee with expertise in medicine,
biostatistics, nutrition, traditional medicines, herbs, aromatherapy, toxicology, biochemistry, botany,
pharmacognosy, pharmacology, pharmacy, and homeopathy was appointed to support the work of the Directorate.
The Natural Health Products Directorate has proposed a regulatory framework for NHPs, which would be
considered a subset of drugs under the Canadian Food and Drugs Act. The Natural Health Product Regulations
were published in the Canada Gazette, Part I, for comment on December 22, 2001. One of the most complex
issues in developing the regulatory framework has been defining what is and is not a natural health product
(Personal communication, M. Cheney, Health Canada, June 11, 2002). The proposed definition of an NHP
contains two parts: a function part and a substance part. The function part captures those substances that are
manufactured, sold, or represented for use in the diagnosis, treatment, mitigation, or prevention of a disease,
disorder, or abnormal physical state or its symptoms in humans; restoring or correcting organic functions in
humans; or maintaining or promoting health or otherwise modifying organic function in humans. This part of the
definition allows for the full range of claims normally associated with drugs.
The substance component of the definition is driven by the medicinal ingredient. There is an inclusion list
of the substances that may be contained within NHPs and an exclusion list of substances that are not NHPs. The
former list includes vitamins, minerals, amino acids and essential fatty acids, probiotics and plant or plant
material alga, fungus or nonhuman animal material or an extract or isolate provided the primary molecular
structure is not altered. Exclusions include antibiotics, biologies, and products administered by injection.
The main components of the proposed NHP Regulations are requirements for product licensing, site
licensing, good manufacturing practices, clinical trials, packaging and labeling, and reporting of adverse
reactions. Under product licensing, each NHP sold in Canada will undergo an assessment before it is authorized
for sale. The application for a product license would be required to provide specific information about the NHP,
including the quantity of medicinal ingredients it contains, the specifications, the intended use or purpose, and
supporting safety and efficacy data. The Natural Health Products Directorate is developing standards of evidence
that will indicate the type of information required to support various claims for NHPs.
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In addition, the applicant for a product license would be required to show that the product will be manufactured,
packaged, labeled, distributed, and imported in accordance with good manufacturing practices.
The regulatory framework proposed will provide for the conduct of clinical trials to allow the industry to
test new products, including products that have not received market authorization, where no other data are
available. The regulations would not place any requirements on the clinical trial investigator, who must be a
health professional regulated by the laws of the province where the clinical trial site is located and whose scope
of practice under those laws must be directly related to the subject matter of the clinical trial. The regulations do
require, however, that one member of the Research Ethics Board of the study be knowledgeable in
complementary or alternative health care. The regulations would require that the trial be conducted in accordance
with good clinical practices and that adverse reactions be reported. Final regulations are expected by the end of
2002 (Personal communication, M.Cheney, Health Canada, June 11, 2002).
EUROPEAN SCIENTIFIC COOPERATIVE ON PHYTOTHERAPY
The European Scientific Cooperative on Phytotherapy (ESCOP) was created in 1989 to promote the
scientific status of phytomedicines and the harmonization of their regulatory status in Europe. ESCOP is an
umbrella organization of national associations for phytotherapy from countries both within and beyond the
European Union. Monographs are produced by a Scientific Committee of ESCOP, a subgroup of delegates from
participating member countries, with expertise in medicine, phytotherapy, pharmacognosy, pharmacology, and
regulatory affairs (ESCOP, 2001). The goal is to compile monographs to provide information on the therapeutic
uses and safety of botanicals that are widely used in European medicine and pharmacy (Blumenthal, 1997;
ESCOP, 2001). Information on quality is not included in these monographs (Blumenthal, 1997).
The Scientific Committee, with assistance from researchers on specific plants, drafts the monographs by
evaluating information from the published scientific literature (ESCOP, 2001). Once a monograph is drafted, it is
reviewed by an independent board of supervising editors, consisting of academic experts in phytotherapy and
medicinal plants. The monographs are then published as fascicules, each containing 10 monographs; 60
monographs have been published to date (ESCOP, 2001).
REFERENCES
AHP (The American Herbal Pharmacopoeia). 2001. Monographs Defined. Developing Quality Control and Therapeutic Monographs:
Monograph Prioritization, Development, Review, Finalization and the Value of Monographs to Health Professionals, Industry and
Consumers. Online. Available at http://www.herbal-ahp.org/mgdefine.html. Accessed November 12, 2001.
AHRQ (Agency for Healthcare Research and Quality). 2002. Evidenced-based Practice Centers. Online. Available at http://www.ahrq.gov/
clinic/epc/. Accessed June 17, 2002.
Blumenthal M. 1997. Herbal monographs. HerbalGram 40:30–38.
Blumenthal M, ed. 1998. Therapeutic Guide to Herbal Medicines. The Complete German Commission E Monographs . Austin, TX:
American Botanical Council.
CRN (Council for Responsible Nutrition). 1998. Reference on Evaluating Botanicals. Washington, DC: CRN.
APPENDIX A
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ESCOP (The European Scientific Cooperative on Phytotherapy). Publications. ESCOP Monographs. Online. Available at http://
www.escop.com/publications.htm. Accessed November 12, 2001.
Foster S, Moley T, Awang D. 1992. Herbs of Commerce. Austin, TX: American Herbal Products Association.
CRC Press.
NMCD (Natural Medicines Comprehensive Database). 2002. About the Database. Online. Available at http://www.naturaldatabase.com/
aboutdb.asp. Accessed January 7, 2002.
Upton R, ed. 1999. American Herbal Pharmacopoeia and Therapeutic Compendium. Valerian Root, Valerian officinalis. Analytical, Quality
Control, and Therapeutic Monograph. Santa Cruz, CA: American Herbal Pharmacopoeia.
USP (The United States Pharmacopeia). 2001. USP Board of Trustees Agrees to Continue Proceeding with Pilot Program for Dietary
Supplement Verification. Online. Available at http://www.usp.org. Accessed October 31, 2001.
USP. 2002a. USP 25-NF 20. Rockville, MD: United States Pharmacopeial Convention, Inc.
USP. 2002b. USP Fact Sheet. Online. Available at http://www.usp.org. Accessed June 18, 2002.
WHO (World Health Organization). 1991. Report of the Consultation to Review the Draft Guidelines for the Assessment of Herbal Remedies.
Munich, Germany, June 19–21, 1991. Geneva: WHO.
WHO. 1999. WHO Monographs on Selected Medicinal Plants, Volume I. Geneva: WHO.
APPENDIX B
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Appendix B
Existing Frameworks or Systems for Evaluating the Safety of
Other Substances
The following text provides an overview of existing safety frameworks that have been developed by federal
agencies, industries, or other organizations. The descriptions are based on presentations to the committee and
information provided by the organizations themselves; the descriptions are not the committee evaluations of the
frameworks. These approaches are also listed in Table 2–2.
PREMARKET APPROVAL OF FOOD ADDITIVES
“Food additives” include an array of substances that accomplish a variety of technical effects in food.
Included are direct food additives (e.g., artificial sweeteners), food-processing aides (e.g., antimicrobials), food
contact substances (e.g., food packaging) and, by legal definition, sources of food irradiation. Under the 1958
Food Additives Amendment (FAA, P.L. 85–929), the Food and Drug Administration (FDA) has responsibility
for the premarket approval of food additives.15 The statute, as interpreted by FDA, establishes both the standard
of data review (i.e., fair evaluation of the data of record), as well as the standard of safety (i.e., a reasonable
certainty of no harm under the intended conditions of use). Notably, the statute exempts from premarket safety
evaluation the use of substances in food that are “generally recognized as safe” (GRAS) by qualified experts in
light of scientific procedures or, for substances used prior to 1958, in light of scientific procedures or experience
based on common use in food. As discussed in the next section, FDA has in place a process for assessing the
worthiness of claims of GRAS status.
FDA conducts safety assessments of new food additives under the principle of establishing a reasonable
certainty of no harm by applying a decision framework. This framework uses a risk assessment approach that
includes the compilation of available data and information, and the application of toxicological and other types
of decision elements.
To assess safety, FDA first examines data on the additive's chemical identity and probable human exposure.
The human exposure data yield the “estimated daily intake” (EDI) of the substance. This value is based on
estimates of the probable intake of high-percentile eaters of the additive over a lifetime of exposure.
15In 1997 the Food, Drug, and Cosmetic Act (FDCA) was amended to provide for premarket notification, rather than
premarket approval, for food contact substances.
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FDA then reviews the available toxicology studies. It has developed guidelines (Toxicological Principles
for the Safety of Food Ingredients, commonly known as The Redbook [FDA/CFSAN, 2001]) for food additive
petitioners to use when assembling the required data in support of their petitioned use. The Redbook outlines the
types of toxicological testing FDA normally expects to be provided in support of the food additive's safety, based
initially on the additive's chemical structure and probable human exposure (The Redbook provides guidance and
is not a requirement). Using this information, FDA assigns additives to initial “concern levels” (or “minimum
testing levels”) of I, II, or III. In its data review, FDA applies toxicological decision elements to further refine the
scope of needed toxicological data.
From the animal studies FDA determines the highest level of intake associated with no adverse
toxicological effects in the most sensitive, longest duration, most relevant animal study. This “highest no-effect
level” is then divided by an “uncertainty factor” (or “safety factor”), often a factor of 100, to account for both
intra- and interspecies variability. The resulting value is the acceptable daily intake (ADI) for the additive. The
ADI is compared to the EDI to determine whether the proposed use of the additive is consistent with a
reasonable certainty of no harm.
For some substances, the traditional risk assessment approach is not applicable. For example, an additive
may be so toxicologically inactive that not enough of the additive can be orally ingested by the test animals to
elicit a toxic response without perturbing normal nutrition. In such cases it is difficult to determine an ADI. FDA
may then employ other types of decision elements. In these cases increased emphasis may be placed on, for
example, chemical identity information and structure-activity relationships; data on absorption, distribution,
metabolism, and excretion; and human tolerance studies (to look at physiological and nutritional responses).
Once all the information has been evaluated, FDA concludes whether the proposed use of a food additive is
consistent with a reasonable certainty of no harm and can be safely marketed. After a new food additive is on the
market, FDA may monitor the substance for safety through examination of available clinical studies and
postmarket surveillance (Personal communication, A.Rulis, FDA, January 25, 2002).
SELECT COMMITTEE ON GRAS SUBSTANCES
Based on the 1958 FAA to the Federal Food, Drug, and Cosmetic Act, FDA developed specific processes to
determine whether substances used in foods were safe for their intended use (see previous section). Food
additives, as defined in the amendment, are subject to premarket approval by FDA unless they are GRAS or fall
within another statutory exception (21 USC321(s)). Requirements for premarket approval are discussed in the
previous section.
For about a dozen years after the passage of the FAA, FDA assumed a lenient approach to dealing with the
GRAS exception. In the early 1970s however, in response to public concern about the apparent carcinogenicity
of cyclamate, which FDA had listed as GRAS, FDA adopted a more rigorous approach (Degnan, 2000). In 1972
FDA contracted with the Life Sciences Research Office (LSRO) of the Federation of American Societies for
Experimental Biology for assistance with a comprehensive review of GRAS substances. LSRO established a
Select Committee on GRAS Substances that examined monographs on each substance that provided all known
data on physical and chemical properties of the substance, human exposure data, animal and human toxicity data,
and reports of special studies on mutagenicity, carcinogenicity, and teratogenicity of the substances. The Select
Committee reached one of five conclusions on each GRAS substance reviewed: (1) continue as GRAS, (2)
continue as GRAS with limitations, (3) uncertainties exist—issue interim food additive order requiring further
testing, but continue as
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GRAS until tests are evaluated, (4) evidence of adverse effects—establish conditions of safe use or remove
GRAS status, or (5) inadequate data precludes evaluation—rescind GRAS status. The review was completed in
1982.
In 1972 FDA also established procedures for petitioning to affirm the GRAS status of a substance, which
are still in use today. Currently, in order to achieve GRAS status for a substance not used in food prior to 1958,
four key criteria must be met: (1) general recognition of safety by qualified experts, (2) the experts must have the
scientific training and experience necessary to evaluate the safety of the substance, (3) experts must base their
safety determination on scientific procedures, and (4) GRAS determination must fully consider the intended use
of the substance (Hallagan and Hall, 1995).
In 1997 FDA proposed to replace the current GRAS affirmation petition scheme with one allowing any
organization to notify FDA of a GRAS determination. The proposed rule would also clarify the types of evidence
needed to establish GRAS status (Degnan, 2000).
GRAS DETERMINATION FOR FLAVOR INGREDIENTS: FEMA EXPERT PANEL
Because flavor ingredients are a type of food additive, the flavor industry has to adhere to the requirements
laid out in the 1958 FAA. To determine GRAS status for flavoring substances, the Flavor and Extract
Manufacturers Association (FEMA), the trade organization of the flavor ingredients industry, created its own
independent expert panel. The FEMA Expert Panel, which has been reviewing flavoring substances since soon
after the passage of the 1958 Amendments, includes qualified experts in toxicology, pharmacology, biostatistics,
pharmacokinetics, biochemistry, pathology, nutrition, organic chemistry, medicinal chemistry, and metabolism
(Woods and Doull, 1991). The panel evaluates the available data on safety and use of flavoring ingredients and
assesses whether the ingredients meet the criteria for GRAS status.
The FEMA Expert Panel has developed a safety assessment evaluation process for determining GRAS
status. Once an application for GRAS status is submitted to the panel with a complete literature search, the first
step is preliminary assessment of the data for adequacy by FEMA staff. These data are then evaluated by the
panel using the following criteria: (1) exposure to the substance in specific foods, (2) natural occurrence in
foods, (3) chemical identity and chemical structure, (4) metabolic and pharmacokinetic characteristics, and (5)
animal toxicity (Woods and Doull, 1991). The panel examines toxicity and metabolic data on structurally similar
compounds (Hallagan and Hall, 1995) and considers the history of use of the substance (Hall, 2001).
Based on the weight of the evidence and expert judgment, the panel reaches one of three conclusions: (1)
GRAS, (2) not GRAS, or (3) insufficient data to determine GRAS status. If data are insufficient, the panel will reexamine the substance after more data is available. The designation of GRAS status on a flavor ingredient must
be based on a unanimous decision by the panel.
COSMETICS INGREDIENT REVIEW
As is the case for dietary supplements, there is also no premarket regulatory system for cosmetic ingredients
other than color additives that are regulated directly by FDA. The Cosmetics Ingredient Review (CIR) Program
was established in 1976 by the Cosmetic, Toiletry,
APPENDIX B
119
and Fragrance Association (CTFA) to review and assess the safety of cosmetic ingredients in the marketplace.
The CIR Program is funded by industry but its review process is independent and open to public and
scientific scrutiny (Bergfeld and Andersen, 2000). Approximately 2,800 cosmetic ingredients were on the market
in 1976 when the CIR Program was established. In response, the CIR Program developed a system to prioritize
these ingredients before performing the safety review. First it excluded or deferred ingredients being reviewed by
other groups, such as fragrances and ingredients being evaluated by FDA, including color additives and over-thecounter drug ingredients. The CIR Program then grouped the remaining ingredients into chemically-related
families and prioritized based on the following factors: frequency of use, ingredient concentration in cosmetic
products, area of human exposure, number of products containing the ingredient used by sensitive population
subgroups (such as infants and the elderly), biological activity, frequency of consumer complaints, and skin
penetration. Using a ranking methodology, ingredients were given a weighted score based on these factors and
were then reviewed in priority order. Frequency of use and biological activity were given the most weight in the
ranking. This priority listing and ranking methodology is updated periodically.
The safety review starts with a comprehensive literature search by CIR staff. The staff summarizes the
available published data and publishes the summaries for public comment. During a 90-day period, interested
parties may submit comments or additional data.
Following this comment period, a CIR Expert Panel begins its review of the collected data and determines
whether more data are needed. The panel consists of seven scientists and physicians who serve as voting
members and three nonvoting liaison members, representing the CTFA, FDA, and Consumer Federation of
America. CIR emphasizes that voting members are careful to avoid any perceived or real conflicts of interest.
Liaison members serve to keep consumer groups, FDA, and the industry informed of the panel's deliberations.
If additional data are required, an informal request is directed toward the cosmetic industry. If data are not
forthcoming or are still inadequate for the safety assessment, a formal request is made. Once all the necessary
data are received, the panel reviews them and produces a tentative report that is released for public comment. At
the end of the comment period, comments are considered and the final report is written.
In determining safety for the final report, the panel looks at all the available data, considers structurally
similar substances, and relies on panel members' experience and expertise. The data needed for the safety
assessment are dependent on the particular ingredient under review. However, the panel usually considers
chemical and physical properties, impurities, extent and type of use, concentration of use, subchronic or chronic
toxicity, skin penetration, skin irritation, and skin sensitization.
In each final report, the CIR Expert Panel reaches one of four conclusions on the safety of a cosmetic
ingredient: (1) safe as currently used, (2) safe with qualifications, (3) unsafe, or (4) insufficient data. If data are
considered insufficient, the panel notes what data are lacking. In practice, this conclusion of insufficient data
encourages manufacturers to undertake additional studies.
NEW DRUGS
Unlike dietary supplements, premarket approval of new drugs places the burden of proof regarding safety
on industry rather than on FDA. The evaluation of new drugs, new uses for approved drugs, and classification of
over-the-counter drugs is an intensive interactive process
APPENDIX B
120
that evaluates both safety and efficacy. Manufacturers that want to develop and market a new drug must follow
the FDA approval process that is modeled on a risk-benefit approach. Approval of a new drug requires extensive
studies of the chemistry, manufacturing, and controls of the drug as well as toxicology and pharmacology of the
compound in animals, and clinical trials of effectiveness and safety in humans. The timeframe and resources for
this process are extensive (Food and Drugs, 21 CFR § 300, 2001).
A key initial step in the drug approval process is submission by the manufacturer of an Investigational New
Drug (IND) application to FDA. The IND is a large collection of information that enables FDA to review the
safety of the substance before clinical testing in humans is allowed to begin. The IND describes the ingredients,
synthesis, manufacturing, purity, and microbiology of the drug product, as well as the stability, packaging, and
labeling. Also included in the IND are data from rodent and nonrodent animal studies, such as pharmacokinetic
and pharmacodynamic data from animal studies, genotoxicity studies, carcinogenicity studies, reproductive and
teratogenic studies, and other toxicological data. When available, the application also includes published or
unpublished human data. Because these data help FDA determine whether the human testing process will be
allowed to proceed, the manufacturer also provides protocols outlining the Phase I, II, and III clinical studies it
plans to conduct. After the IND is submitted, FDA has 30 days to review its content. If FDA does not contact the
sponsor within that time, the proposed Phase I study may begin (Food and Drugs, 21 CFR § 312, 2001).
During Phase I studies, which focus on safety but not efficacy, human volunteers (who are usually healthy)
are carefully monitored for tolerability, and pharmacokinetic data are often collected. The aim of Phase II is to
evaluate the dose-response relationship and effectiveness of the drug in a few hundred subjects who have the
disorder the drug is intended to treat. These studies are usually double-blind and placebo-controlled to minimize
investigator and subject bias. Phase III of the investigation consists of well-controlled trials to gather evidence on
both effectiveness and safety of the drug and information needed for labeling. These are large trials of several
hundred to several thousand subjects.
The data collected in all of the clinical studies enable FDA to approve or disapprove a drug based on a riskbenefit analysis. Once a drug is approved and marketed, additional safety information continues to be collected
through mandatory submission of adverse event information from the manufacturer to FDA via MedWatch and
other reporting mechanisms. FDA may also require the manufacturer to conduct postmarketing studies.
OVER-THE-COUNTER DRUGS
The process above describes the steps required for a new drug approval (NDA). In the years after proof of
effectiveness was added to the NDA requirements, FDA wrestled with how to deal with the thousands of overthe-counter (OTC) drugs that were on the market though not covered by approved NDAs. Rather than make caseby-case challenges to such products, FDA decided to review them by therapeutic class, with the assistance of
expert advisory committees. The process that FDA established to accomplish this mission is known as the OTC
Drug Review.
In 1972 FDA, with the help of 17 advisory panels, began its review of the more than 700 active ingredients
with almost 1,500 uses in marketed OTC drug products. The aim of the review was to prepare monographs
establishing the conditions under which OTC drugs would be considered generally recognized as safe and
effective and not misbranded, and thus exempt from the NDA process.
APPENDIX B
121
The OTC Drug Review consists of several phases. In the first phase, now complete, the advisory panels
made recommendations regarding the categorization of products. Category I was for those drugs that the panel
deemed to be generally recognized as safe and effective and not misbranded if they satisfied specified
conditions, including, among others, active ingredients and labeling indications. Category II was for products
with active ingredients, labeling claims, or other conditions that resulted in them not being generally recognized
as safe or effective or resulted in them being misbranded. Category III was for products with active ingredients,
labeling claims, or other conditions for which the data were insufficient and for which further testing was thus
required.
In the second phase of the review, FDA published the panels' recommendations as Advanced Notices of
Proposed Rulemaking (ANPRs). These ANPRs included proposed monographs establishing the conditions under
which OTC drugs in specific therapeutic classes would be generally recognized as safe and effective and not
misbranded (Category I). In the third phase, after considering the public comments received in response to the
ANPRs, the agency issued proposed rules designated Tentative Final Monographs (TFMs). In the final step of
the process, the agency, after receiving further comments, publishes final monographs. As of March 1, 2001,
most, but not all, of these final monographs had been published (CDER, 2001). Final monographs set forth the
mandatory conditions for an OTC drug to be considered generally recognized as safe and effective and not
misbranded, including active ingredients, dosages, permitted combinations of ingredients, warnings, and labeling
requirements.
NEW CHEMICALS PROGRAM
Under the New Chemicals Program, the Environmental Protection Agency (EPA) is given the authority to
regulate the entry and use of new chemicals into the U.S. marketplace. This program, mandated by Section 5 of
the Toxic Substances Control Act (TSCA) in 1976, seeks to manage the potential risk from new chemicals both
to humans and to the environment. Manufacturers or importers of new chemicals are required under TSCA to
notify EPA through a premanufacturer notice (PMN) that must be submitted at least 90 days prior to
manufacture or import of the new chemical. New chemicals are defined as those that are not listed on EPA's
TSCA Chemical Substance Inventory of existing chemicals. The burden of proof for identifying risk rests with
EPA.
EPA receives petitions for approximately 2,000 new chemicals from manufacturers each year (Personal
communication, L.Scarano, EPA, October 11, 2001). At submission, the manufacturer provides the PMN, which
includes information on chemical and physical identity and properties, product uses, proposed production or
importation volume, by-products, human exposure, disposal practices, environmental releases, pollution
prevention efforts, and available information on health or environmental effects. A multidisciplinary team of
experts is responsible for reviewing the information provided in the PMN for safety. The first step is to
determine whether the substance is already on the TSCA inventory. If not already on the inventory, the team then
evaluates chemical structure, how the chemical is synthesized, the intended use of the chemical, and the physical
and chemical properties of the chemical. They also check for analogs in an EPA analog database. About 30
percent of the applications are not reviewed after this stage; these substances consist of polymers, which because
of their molecular weight and other properties are considered unlikely to present significant hazard potential.
The next step of the process is to estimate the potential environmental and health hazards using analog
analysis, quantitative structure activity relationship models, and expert judgment.
APPENDIX B
122
The structure activity team has identified 54 structural alert categories that may indicate a potential concern for
chemicals that fall into these categories (Personal communication, L. Scarano, EPA, October 11, 2001).
The third step is to prioritize the results of the safety evaluations and to decide if further review is
warranted. If further review is required, the next step is a more detailed standard review. In this step, a risk
assessment is conducted, human health hazard information is evaluated, and the chemical is assigned a
qualitative determination of the hazard concern level. Evidence of adverse effects in human populations and
conclusive evidence of severe effects in animal studies constitute a high hazard concern level. A moderate level
of concern results from suggestive animal studies and analogue data and knowledge that the chemical class has
produced toxicity. The low concern level is for those chemicals for which no concern was identified. At this
point, depending on the hazard concern level and considering the estimated exposures and releases, EPA will
inform the manufacturer that the chemical presents potential risk issues and that more testing is needed. If EPA
does not act to regulate the chemical, the manufacturer may commence production or importation.
TOLERABLE UPPER INTAKE LEVEL MODEL FOR NUTRIENTS
A risk assessment model for nutrients has been developed by the Food and Nutrition Board of the Institute
of Medicine (IOM, 1998). This model is consistent with contemporary risk assessment practices and results in a
characterization of the relationship between the exposure (intake) of a nutrient and the likelihood of adverse
health effects in exposed individuals. The Tolerable Upper Intake Level (UL) is defined as the “highest level of
daily nutrient intake that is likely to pose no risk of adverse health effects for almost all individuals in the general
population. As intake increases above the UL, the potential risk of adverse effects increases” (IOM, 1998).
Determination of the UL is one aspect in the process for determining nutrient-based reference values,
known as Dietary Reference Intakes (DRIs), that is being undertaken by the Food and Nutrition Board. DRIs are
comprised of the Recommended Dietary Allowance (RDA), the Adequate Intake, the Estimated Average
Requirement, and the UL. The UL model differs from the process for determining the RDA because the RDA is
a recommended intake whereas the UL is an intake level that individuals should not exceed on a chronic basis.
Evaluation of data to establish a UL are completed for all nutrients that are being reviewed in the DRI process,
but not all nutrients have ULs; for some nutrients insufficient data is available upon which to base a UL.
The UL model for nutrients is a four-step process. The first step is hazard identification. At this step a
thorough literature review is performed for each nutrient and all information pertaining to the adverse effects of
chronic intake is examined and evaluated. Data from human, animal, and in vitro studies are used to address
evidence of adverse effects in humans, causality, relevance of experimental data, pharmacokinetic and metabolic
data, mechanisms of toxic action, quality and completeness of the data, and identification of sensitive
populations. Scientific judgment of the committee members responsible for developing ULs is key to reaching a
conclusion on the nutrient's ability to cause an adverse effect in humans when consumed on a chronic basis.
The next step is a dose-response assessment to determine the relationship between nutrient intake and the
adverse effect. In this step, the most critical data sets for deriving the UL are selected. Human data are preferable
to animal or in vitro data for evaluating adverse effects. The route of exposure, magnitude and duration of
exposure, and the critical endpoint are identified. A
APPENDIX B
123
no-observed-adverse-effect level (NOAEL) and lowest-observed-adverse-effect level (LOAEL) are determined
based on these factors if data are available to do so. Next, an uncertainty factor is applied to the NOAEL or
LOAEL. The uncertainty factor is based on expert judgment of the uncertainties of extrapolating from the
observed data to the general population. Dividing the NOAEL or LOAEL by the uncertainty factor results in the
UL.
The third step is an assessment of the range and distribution of intake or exposure of the nutrient or food
component in the general population. If the adverse effect appears to be associated with intake from dietary
supplements only, then the UL is for supplements only. It is clearly indicated whether the UL is for total intake,
intake from supplements only, or intake from fortified foods and supplements.
The last step is a characterization of the risk. The range of reported intakes of the nutrient is compared with
the UL. If a large fraction of the general population is consuming chronic intakes above the UL, this could be a
potential at-risk group. The UL does not include policy decisions, but the rationale suggests risk management
guidelines for determining the significance of the risk to a population consuming a nutrient at levels above the
UL.
REFERENCES
Bergfeld WF, Andersen FA. 2000. The cosmetic ingredient review. In: Estrin NF, Akerson JM, eds. Cosmetic Regulation in a Competitive
Environment. New York: Marcel Dekker. Pp. 195–216.
CDER (Center for Drug Evaluation and Research). 2001. Milestone Status of OTC Drug Review Documents as of March 1, 2001. Online.
Food and Drug Administration. Available at http://www.fda.gov/cder/otc/milestone/pdf. Accessed March 28, 2002.
CFSAN (Center for Food Safety and Applied Nutrition). 2001. Toxicological Principles for the Safety of Food Ingredients. Redbook 2000.
Available at http://www.cfsan.fda.gov/~redbook/red-toca.html. Accessed March 28, 2002.
Degnan FH. 2000. FDA's Creative Application of the Law. Washington, DC: Food, Drug, and Law Institute. Pp. 19–26.
Hallagan JB, Hall RL. 1995. FEMA GRAS—A GRAS assessment program for flavor ingredients. Flavor and Extract Manufacturers
Association. Regul Toxicol Pharmacol 21:422–430.
IOM (Institute of Medicine). 1998. Dietary Reference Intakes. A Risk Assessment Model for Establishing Upper Intake Levels for Nutrients.
Washington, DC: National Academy Press.
Woods LA, Doull J. 1991. GRAS evaluation of flavoring substances by the Expert Panel of FEMA. Regul Toxicol Pharmacol 14:48–58.
APPENDIX C
124
Appendix C
Possible Combinations of Scores
There are 625 possible combinations of scores that fall under Priority Groups I through V. These are all
listed below, in the priority order that would be indicated by the proposed framework. As described in Chapter 5,
high prevalence of use would shift supplements to the highest priority within each Priority Group. NAD=no
appropriate data.
Priority Group
I
Human Data
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
Animal Data
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
Structure Data
3
3
3
3
3
2
NAD
1
0
2
2
2
2
NAD
NAD
NAD
NAD
1
1
1
1
0
0
0
0
In Vitro Data
3
2
NAD
1
0
3
3
3
3
2
NAD
1
0
2
NAD
1
0
2
NAD
1
0
2
NAD
1
0
APPENDIX C
Priority Group
II
125
Human Data
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
Animal Data
2
NAD
1
0
2
2
2
2
2
2
2
2
NAD
NAD
NAD
NAD
NAD
NAD
NAD
NAD
1
1
1
1
1
1
1
1
0
0
0
0
0
0
0
0
2
2
2
2
2
2
2
2
2
2
2
2
Structure Data
3
3
3
3
3
3
3
3
2
NAD
1
0
3
3
3
3
2
NAD
1
0
3
3
3
3
2
NAD
1
0
3
3
3
3
2
NAD
1
0
2
2
2
2
NAD
NAD
NAD
NAD
1
1
1
1
In Vitro Data
3
3
3
3
2
NAD
1
0
3
3
3
3
2
NAD
1
0
3
3
3
3
2
NAD
1
0
3
3
3
3
2
NAD
1
0
3
3
3
3
2
NAD
1
0
2
NAD
1
0
2
NAD
1
0
APPENDIX C
Priority Group
II
126
Human Data
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
Animal Data
2
2
2
2
NAD
NAD
NAD
NAD
NAD
NAD
NAD
NAD
NAD
NAD
NAD
NAD
NAD
NAD
NAD
NAD
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
0
0
0
0
0
0
0
0
0
0
0
0
Structure Data
0
0
0
0
2
2
2
2
NAD
NAD
NAD
NAD
1
1
1
1
0
0
0
0
2
2
2
2
NAD
NAD
NAD
NAD
1
1
1
1
0
0
0
0
2
2
2
2
NAD
NAD
NAD
NAD
1
1
1
1
In Vitro Data
2
NAD
1
0
2
NAD
1
0
2
NAD
1
0
2
NAD
1
0
2
NAD
1
0
2
NAD
1
0
2
NAD
1
0
2
NAD
1
0
2
NAD
1
0
2
NAD
1
0
2
NAD
1
0
2
NAD
1
0
APPENDIX C
Priority Group
II
III
127
Human Data
3
3
3
3
NAD
2
1
0
NAD
NAD
NAD
NAD
NAD
NAD
NAD
NAD
2
2
2
2
2
2
2
2
1
1
1
1
1
1
1
1
0
0
0
0
0
0
0
0
NAD
NAD
NAD
NAD
NAD
NAD
NAD
NAD
Animal Data
0
0
0
0
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
Structure Data
0
0
0
0
3
3
3
3
3
3
3
3
2
NAD
1
0
3
3
3
3
2
NAD
1
0
3
3
3
3
2
NAD
1
0
3
3
3
3
2
NAD
1
0
2
2
2
2
NAD
NAD
NAD
NAD
In Vitro Data
2
NAD
1
0
3
3
3
3
2
NAD
1
0
3
3
3
3
2
NAD
1
0
3
3
3
3
2
NAD
1
0
3
3
3
3
2
NAD
1
0
3
3
3
3
2
NAD
1
0
2
NAD
1
0
APPENDIX C
Priority Group
III
128
Human Data
NAD
NAD
NAD
NAD
NAD
NAD
NAD
NAD
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
0
0
0
0
0
0
0
0
Animal Data
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
Structure Data
1
1
1
1
0
0
0
0
2
2
2
2
NAD
NAD
NAD
NAD
1
1
1
1
0
0
0
0
2
2
2
2
NAD
NAD
NAD
NAD
1
1
1
1
0
0
0
0
2
2
2
2
NAD
NAD
NAD
NAD
In Vitro Data
2
NAD
1
0
2
NAD
1
0
2
NAD
1
0
2
NAD
1
0
2
NAD
1
0
2
NAD
1
0
2
NAD
1
0
2
NAD
1
0
2
NAD
1
0
2
NAD
1
0
2
NAD
1
0
2
NAD
1
0
APPENDIX C
Priority Group
III
IV
129
Human Data
0
0
0
0
0
0
0
0
NAD
NAD
NAD
NAD
2
2
2
2
1
1
1
1
0
0
0
0
NAD
NAD
NAD
NAD
NAD
NAD
NAD
NAD
NAD
NAD
NAD
NAD
NAD
NAD
NAD
NAD
2
2
2
2
2
2
2
2
Animal Data
3
3
3
3
3
3
3
3
2
NAD
1
0
2
NAD
1
0
2
NAD
1
0
2
NAD
1
0
2
2
2
2
NAD
NAD
NAD
NAD
1
1
1
1
0
0
0
0
2
2
2
2
2
2
2
2
Structure Data
1
1
1
1
0
0
0
0
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
2
NAD
1
0
In Vitro Data
2
NAD
1
0
2
NAD
1
0
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
2
NAD
1
0
2
NAD
1
0
2
NAD
1
0
2
NAD
1
0
2
NAD
1
0
3
3
3
3
APPENDIX C
Priority Group
IV
130
Human Data
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
NAD
NAD
NAD
NAD
NAD
NAD
NAD
NAD
NAD
NAD
NAD
NAD
NAD
NAD
NAD
NAD
1
1
1
1
1
1
1
1
Animal Data
NAD
NAD
NAD
NAD
NAD
NAD
NAD
NAD
1
1
1
1
1
1
1
1
0
0
0
0
0
0
0
0
2
2
2
2
NAD
NAD
NAD
NAD
1
1
1
1
0
0
0
0
2
2
2
2
2
2
2
2
Structure Data
3
3
3
3
2
NAD
1
0
3
3
3
3
2
NAD
1
0
3
3
3
3
2
NAD
1
0
2
NAD
1
0
2
NAD
1
0
2
NAD
1
0
2
NAD
1
0
3
3
3
3
2
NAD
1
0
In Vitro Data
2
NAD
1
0
3
3
3
3
2
NAD
1
0
3
3
3
3
2
NAD
1
0
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
2
NAD
1
0
3
3
3
3
APPENDIX C
Priority Group
IV
131
Human Data
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
Animal Data
NAD
NAD
NAD
NAD
NAD
NAD
NAD
NAD
1
1
1
1
1
1
1
1
0
0
0
0
0
0
0
0
2
2
2
2
2
2
2
2
NAD
NAD
NAD
NAD
NAD
NAD
NAD
NAD
1
1
1
1
1
1
1
1
Structure Data
3
3
3
3
2
NAD
1
0
3
3
3
3
2
NAD
1
0
3
3
3
3
2
NAD
1
0
3
3
3
3
2
NAD
1
0
3
3
3
3
2
NAD
1
0
3
3
3
3
2
NAD
1
0
In Vitro Data
2
NAD
1
0
3
3
3
3
2
NAD
1
0
3
3
3
3
2
NAD
1
0
3
3
3
3
2
NAD
1
0
3
3
3
3
2
NAD
1
0
3
3
3
3
2
NAD
1
0
3
3
3
3
APPENDIX C
Priority Group
IV
V
132
Human Data
0
0
0
0
0
0
0
0
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
Animal Data
0
0
0
0
0
0
0
0
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
NAD
NAD
NAD
NAD
NAD
NAD
NAD
NAD
NAD
NAD
NAD
NAD
NAD
NAD
NAD
NAD
1
1
1
1
1
1
1
1
Structure Data
3
3
3
3
2
NAD
1
0
2
2
2
2
NAD
NAD
NAD
NAD
1
1
1
1
0
0
0
0
2
2
2
2
NAD
NAD
NAD
NAD
1
1
1
1
0
0
0
0
2
2
2
2
NAD
NAD
NAD
NAD
In Vitro Data
2
NAD
1
0
3
3
3
3
2
NAD
1
0
2
NAD
1
0
2
NAD
1
0
2
NAD
1
0
2
NAD
1
0
2
NAD
1
0
2
NAD
1
0
2
NAD
1
0
2
NAD
1
0
2
NAD
1
0
APPENDIX C
Priority Group
V
133
Human Data
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
NAD
NAD
NAD
NAD
NAD
NAD
NAD
NAD
NAD
NAD
NAD
NAD
NAD
NAD
NAD
NAD
NAD
NAD
NAD
NAD
NAD
NAD
NAD
NAD
NAD
Animal Data
1
1
1
1
1
1
1
1
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
NAD
NAD
NAD
NAD
NAD
NAD
NAD
NAD
NAD
Structure Data
1
1
1
1
0
0
0
0
2
2
2
2
NAD
NAD
NAD
NAD
1
1
1
1
0
0
0
2
2
2
2
NAD
NAD
NAD
NAD
1
1
1
1
0
0
0
0
2
2
2
2
NAD
NAD
NAD
NAD
1
In Vitro Data
2
NAD
1
0
2
NAD
1
0
2
NAD
1
0
2
NAD
1
0
2
NAD
1
0
2
NAD
1
2
NAD
1
0
2
NAD
1
0
2
NAD
1
0
2
NAD
1
0
2
NAD
1
0
2
NAD
1
0
2
APPENDIX C
Priority Group
V
134
Human Data
NAD
NAD
NAD
NAD
NAD
NAD
NAD
NAD
NAD
NAD
NAD
NAD
NAD
NAD
NAD
NAD
NAD
NAD
NAD
NAD
NAD
NAD
NAD
NAD
NAD
NAD
NAD
NAD
NAD
NAD
NAD
NAD
NAD
NAD
NAD
NAD
NAD
NAD
NAD
1
1
1
1
1
1
1
1
1
Animal Data
NAD
NAD
NAD
NAD
NAD
NAD
NAD
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
2
2
2
2
2
2
2
2
2
Structure Data
1
1
1
0
0
0
0
2
2
2
2
NAD
NAD
NAD
NAD
1
1
1
1
0
0
0
0
2
2
2
2
NAD
NAD
NAD
NAD
1
1
1
1
0
0
0
0
2
2
2
2
NAD
NAD
NAD
NAD
1
In Vitro Data
NAD
1
0
2
NAD
1
0
2
NAD
1
0
2
NAD
1
0
2
NAD
1
0
2
NAD
1
0
2
NAD
1
0
2
NAD
1
0
2
NAD
1
0
2
NAD
1
0
2
NAD
1
0
2
NAD
1
0
2
APPENDIX C
Priority Group
V
135
Human Data
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
Animal Data
2
2
2
2
2
2
2
NAD
NAD
NAD
NAD
NAD
NAD
NAD
NAD
NAD
NAD
NAD
NAD
NAD
NAD
NAD
NAD
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
0
0
0
0
0
0
0
0
0
Structure Data
1
1
1
0
0
0
0
2
2
2
2
NAD
NAD
NAD
NAD
1
1
1
1
0
0
0
0
2
2
2
2
NAD
NAD
NAD
NAD
1
1
1
1
0
0
0
0
2
2
2
2
NAD
NAD
NAD
NAD
1
In Vitro Data
NAD
1
0
2
NAD
1
0
2
NAD
1
0
2
NAD
1
0
2
NAD
1
0
2
NAD
1
0
2
NAD
1
0
2
NAD
1
0
2
NAD
1
0
2
NAD
1
0
2
NAD
1
0
2
NAD
1
0
2
APPENDIX C
Priority Group
V
136
Human Data
1
1
1
1
1
1
1
1
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
Animal Data
0
0
0
0
0
0
0
0
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
NAD
NAD
NAD
NAD
NAD
NAD
NAD
NAD
NAD
NAD
NAD
NAD
NAD
NAD
NAD
NAD
1
1
1
1
1
1
1
1
Structure Data
1
1
1
0
0
0
0
0
2
2
2
2
NAD
NAD
NAD
NAD
1
1
1
1
0
0
0
0
2
2
2
2
NAD
NAD
NAD
NAD
1
1
1
1
0
0
0
0
2
2
2
2
NAD
NAD
NAD
NAD
In Vitro Data
NAD
1
0
2
NAD
1
0
0
2
NAD
1
0
2
NAD
1
0
2
NAD
1
0
2
NAD
1
0
2
NAD
1
0
2
NAD
1
0
2
NAD
1
0
2
NAD
1
0
2
NAD
1
0
2
NAD
1
0
APPENDIX C
Priority Group
V
137
Human Data
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
Animal Data
1
1
1
1
1
1
1
1
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
Structure Data
1
1
1
1
0
0
0
0
2
2
2
2
NAD
NAD
NAD
NAD
1
1
1
1
0
0
0
0
In Vitro Data
2
NAD
1
0
2
NAD
1
0
2
NAD
1
0
2
NAD
1
0
2
NAD
1
0
2
NAD
1
0
APPENDIX D
138
Appendix D
Table of Food and Drug Administration Actions on Dietary
Supplements
This table provides an abbreviated list of some of the Food and Drug Administration (FDA) actions that
have been described on the FDA Medwatch website: http//www.fda.gov/medwatch/safety.htm.
TABLE D-1 Abbreviated List of FDA Actions on Dietary Supplements
FDA Action
Year Dietary Supplement
2002 PC SPES
FDA warned consumers to stop use
2001 Aristolochic Acid
FDA issued a Consumer Advisory advising consumers to immediately discontinue use
FDA sent updated letters to industry and health care professionals (HCPs) about the safety
concerns of these products
FDA requested voluntary recall by manufacturers and distributors; several issued a recall
2001 Comfrey
FDA recommended that manufacturers remove product from the market and alert
customers to immediately stop use
2001 Kava
FDA requested HCPs to review liver toxicity cases and to report possible kava-related
cases to MedWatch
2001 Lipokinetix
FDA warned consumers to stop use immediately
FDA alerted HCPs that Lipokinetix may be a serious health risk and asked HCPs to review
and report cases of possible Lipokinetix-related hepatitis
FDA recommended to distributor that it remove product from market and alert customers
2001 Neo Concept Aller Relief FDA informed manufacturer of possible contamination of the product and manufacturer
issued recall
2000 St. John's Wort
FDA notified HCP of the risk of drug interactions
2000 Tiratricol
APPENDIX D
139
Year Dietary Supplement
1999 Asian Remedy for Menstrual Cramps—Koo Sar
1999 Gamma Butyrolactone (GBL)
1999 GBL, Gamma Hydroxybutyric Acid (GHB) and 1,4
Gutanediol (BD)
1999 GBL-Related Products
1998 “Sleeping Buddha”
1998 5-hydroxy-L-tryptophan
1998 Cholestin
1997 Chomper
1997 Ephedrine Dietary Supplements
1997 Gamma Hydroxybutyric Acid (GHB)
1997 “Herbal Fen-Phen”
1997 Infant Formula (homemade)
1997 “Plantain” Containing Dietary Supplements
1996 Street Drugs Containing Botanical Ephedrine
1992 Chaparral
FDA Action
Centers for Diseaase Control and Prevention report
attributed lead poisoning case to product (posted on FDA
website)
FDA warned consumers not to consume
FDA requested manufacturers to voluntarily recall
products (at least one manufacturer agreed to recall)
FDA notified HCPs and continues to warn public that
these substances are unapproved new drugs that may
cause harm
FDA conducted seizures of product
FDA warned the public that these are unapproved new
drugs that may cause harm
FDA conducted seizures of product
FDA warned consumers not to use product because it
contains an unlabeled prescription drug ingredient
FDA noted the presence of impurities in some products
FDA determined product was an unapproved drug (later
upheld by court rulinga)
FDA warned consumers not to consume product
FDA proposed limits to epedrine alkaloids allowed in
products. Proposes adding warnings and information in
labeling and marketing
FDA reissued warning against use of substance because
it is an unapproved and potentially dangerous new drug
FDA and Department of Justice took enforcement
actions (restrict importation, embargoes, etc.)
FDA warned consumers that product is an unapproved
and potentially dangerous new drug
FDA took action to remove product from the market
FDA informed pediatricians about safety concerns with
use
FDA warned consumers not to consume dietary
supplement products containing plantain because of
possible digitalis contamination
FDA worked with manufacturers to identify and recall
possibly contaminated products
FDA warned consumers not to consume products
a
The most recent court ruling held that cholestin was a drug and would be subject to regulation by FDA; however, the case is being appealed
(Pharmanex v. Shalala, No. 2:97CV262k, 2001 WL 741419 [D. Utah March 30, 2001], appeal docketed, No. 01–4108 [10th Cir. May 31,
2001]).
APPENDIX E
140
Appendix E
Presenters at the Open Sessions of the Project on the
Framework for Evaluating the Safety of Dietary Supplements
F.Alan Andersen, Cosmetic Ingredient Review, Washington, D.C.
Dennis V.C.Awang, Mediplant, British Columbia
Joseph M.Betz, Office of Dietary Supplements, National Institutes of Health, Bethesda, MD
Paul Coates, Office of Dietary Supplements, National Institutes of Health, Bethesda, MD
Annette Dickinson, Council for Responsible Nutrition, Washington, D.C.
David J.Graham, Center for Drug Evaluation and Research, Food and Drug Administration, Rockville, MD
Richard L.Hall, Flavor and Extract Manufacturers Association, Towson, MD
Claire L.Kruger, ENVIRON International Corporation, Arlington, VA
Gilbert A.Leveille, McNeill Consumer Healthcare, Fort Washington, PA
Christine Lewis Taylor, Center for Food Safety and Applied Nutrition, Food and Drug Administration, College
Park, MD
Hulon McCain, Whitehall-Robins Healthcare, Madison, NJ
Sanford Miller, Bethesda, MD
Joseph V.Rodricks, ENVIRON International Corporation, Arlington, VA
Alan Rulis, Center for Food Safety and Applied Nutrition, Food and Drug Administration, College Park, MD
Louis Scarano, Environmental Protection Agency, Washington, D.C.
David Schardt, Center for Science in the Public Interest, Washington, D.C.
Bruce Silverglade, Center for Science in the Public Interest, Washington, D.C.
R.William Soller, Consumer Healthcare Products Association, Washington, D.C.
Susan Trimbo, Nutricia, Boca Raton, FL
Sidney M.Wolfe, Public Citizen's Health Research Group, Washington, D.C.
APPENDIX F
141
Appendix F
Biographical Sketches of Committee Members
Barbara O.Schneeman, Ph.D. (chair) served formerly as dean, College of Agricultural and Environmental
Sciences, and currently serves as a professor of nutrition in the Department of Nutrition and in the Division of
Clinical Nutrition and Metabolism, University of California at Davis. Her professional activities include
membership on the U.S. Department of Agriculture (USDA)/Department of Health and Human Services 1990
and 1995 Dietary Guidelines for Americans Advisory Committees, the Board of Trustees of the International
Life Sciences Institute, and the editorial boards of Proceedings of the Society of Experimental Biology and
Medicine, Food and Nutrition Series of Academic Press, Nutrition Reviews, Journal of Nutrition, and California
Agriculture. Professional honors include the Institute of Food Technologists' Samuel Gate Prescott Award for
research, the Commissioner's Special Citation, and the Harvey W.Wiley Medal from the Food and Drug
Administration (FDA) in recognition of her contributions toward the advancement of scientific research. Dr.
Schneeman has also been active in developing state and national nutrition policy as an appointed member of the
California State Board of Food and Agriculture and the USD A Public Advisory Board. She is currently
president of the Dannon Institute, a nonprofit foundation funded by Dannon, Inc. She has served as chair of the
Institute of Medicine (IOM) Committee on Body Composition, Nutrition, and Health of Military Women and
recently served as Deputy Administrator for Human Nutrition of the USDA Agricultural Research Service (on
leave from U.C. Davis). Dr. Schneeman's research areas include fat absorption, complex carbohydrates, dietary
fiber, and gastrointestinal function.
Daniel L.Azarnoff, M.D. is president of D.L.Azarnoff Associates, through which he does consulting with
the pharmaceutical industry. He also serves as Senior Vice President of Clinical/Regulatory Affairs at Cellegy
Pharmaceuticals, Inc. The companies he is involved with do not market dietary supplements. Dr. Azarnoff s
expertise includes pharmaceutical industry administration, pharmacology, clinical pharmacology, and general
internal medicine. His research interests include the drug approval process, including preclinical (pharmacology,
toxicology, pharmaceutics) and clinical (therapeutic, bioequivalence trials); drugs to treat hyperlipoproteinemia;
and transdermal drug delivery. Dr. Azarnoff earned his M.D. from the University of Kansas where he became
KUMC Distinguished Professor of Medicine and Pharmacology and previously served as President of Research
and Development for the Searle Pharmaceutical Company. He has been an IOM member since 1978 with
membership on
APPENDIX F
142
numerous IOM committees including the Committee on Halcion, the Committee on Understanding the Biology
of Sex and Gender Differences, and the Committee to Assess the System for the Protection of Human Research
Subjects.
Cindy L.Christiansen, Ph.D. is chief of the Statistics Section, Center for Health Quality, Outcomes, and
Economic Research at Bedford Veterans Affairs and an associate professor of health services at Boston
University. Dr. Christiansen serves as chair of the American Statistical Association Section on Health Policy
Statistics. She is one of the country's leading experts on hierarchical and predictive models and their use in health
services research. Her research interests include the development and implementation of multi-level and
prediction models for health service and medical applications, and her methodological work has focused on
Poisson models and on models for grouped ordinal data.
Alice M.Clark, Ph.D. holds her Ph.D. in pharmacognosy from the University of Mississippi and serves as
Vice Chancellor for Research and Sponsored Programs, Frederick A.P.Barnard Distinguished Professor of
Pharmacognosy and research professor of the Research Institute of Pharmaceutical Sciences at the University of
Mississippi. Prior to assuming her current position in July 2001, Dr. Clark was director of the National Center
for Natural Products Research, which operates as a drug discovery and development program that works on
acquisition, preparation, and in vitro evaluation of extracts of higher plants for beneficial activity. It combines
drug discovery, in vitro, and in vivo evaluations of efficacy and toxicity, working in collaboration with USDA's
Agriculture Research Service and industry to develop therapeutics from plants. Faculty at the Center conduct
research on dietary supplements and potential therapeutics. The Center is well known for its efforts in enhancing
the safety and efficacy of botanical dietary supplements. Dr. dark's research interests are in evaluation of natural
compounds for antibiotic and antifungal activity, as well as in the utilization of microorganisms as predictive
models for drug metabolism and as synthetic adjuncts. She is part of an NCNPR group working on a Centers for
Disease Control and Prevention-funded project to evaluate the potential for botanical dietary supplements to
interact with pharmaceuticals, to review the scientific literature on specific botanicals, and to review consumer
use of botanical dietary supplements. Dr. Clark also serves as associate editor for the Journal of Natural Products.
Norman R.Farnsworth, Ph.D. is a distinguished university professor, research professor of
pharmacognosy, director of the Pharmacognosy Graduate Program, and the director of the Program for
Collaborative Research in the Pharmaceutical Sciences at the University of Illinois at Chicago (UIC). Dr.
Farnsworth also serves as director of the UIC/National Institutes of Health (NIH) Dietary Supplements Research
Center. He is credited with designing a worldwide computer database called NAPRALERT that compiles
scientific literature on the safety and efficacy of herbal medicines, plants, marine organisms, and fungi. As
director of the World Health Organization (WHO) Collaborating Center for Traditional Medicine, Dr.
Farnsworth has used this database to lead the WHO'S publication of numerous monographs reviewing traditional
medicinals. He is a member of Health Canada's Expert Advisory Committee on Natural Health Products and
served on the Commission on Dietary Supplement Labels authorized by the Dietary Supplement Health and
Education Act of 1994. Dr. Farnsworth serves on the Scientific Advisory Board of the Herb Research
Foundation, the Board of Trustees of the American Botanical Council, and the editorial advisory board of several
peer-reviewed journals and Herbalgram. He
APPENDIX F
143
also consults with various companies on pharmacognosy questions (currently these include Pharmavite, Shaklee,
and Tom's of Maine). He has authored a number of publications about botanicals, including Botanical Dietary
Supplements: Quality, Safety, and Efficacy. His research interests include analysis of chemical and biological
data on natural products and isolation, identification, and structure elucidation of biologically active plant
constituents.
Ted Gansler, M.D., M.B.A. is Director of Medical Information Strategy at the American Cancer Society
(ACS) and editor of the ACS publication, CA: A Cancer Journal for Clinicians. At ACS, Dr. Gansler is
responsible for assuring the accuracy of printed and electronic information products for patients, the general
public, and health professionals. He is a graduate of Duke University, University of Pittsburgh School of
Medicine, and Georgia State University School of Business Administration, and completed a pathology
residency and cytopathology fellowship at the University of Pennsylvania. Dr. Gansler is also an adjunct
associate professor of pathology at Emory University.
Philip S.Guzelian, M.D. serves as the Director of Medical Toxicology and co-director of the Hepatobiliary
Research Center at the University of Colorado Health Sciences Center. Dr. Guzelian earned his M.D. at the
University of Wisconsin-Madison. His research interests, largely supported by grants from NIH, include liver
disease, hepatic drug metabolism and toxicity, medical toxicology, and cytochrome P450. His research objective
is to understand how cells recognize the presence of foreign chemicals and activate host defenses. Dr. Guzelian
has been a member of the NIH National Advisory Environmental Health Sciences Council, chairman of the
Toxicology Advisory Committee of the Burroughs Wellcome Fund, and a member of the Drug Safety Scientific
Advisory Committee for Rhone-Poulenc Rorer Pharmaceuticals, the Board of Scientific Directors of the
International Life Sciences Institute, and the Board of Scientific and Policy Advisors of the American Council of
Science and Health. He is also an ad hoc member of the Environmental Protection Agency's (EPA) Office of
Science Coordination and Policy Scientific Advisory Panel and has served on EPA's Science Review Board for
the Food Quality Protection Act.
Elizabeth Jeffery, Ph.D. serves as a professor of nutritional toxicology for the Department of Food Science
and Human Nutrition, the Division of Nutritional Sciences and the Department of Pharmacology at the
University of Illinois, Urbana-Champaign. She has a Ph.D. in biochemistry from the University of London
(United Kingdom) and teaches and conducts research in the area of safety and efficacy of functional foods and
dietary supplements. Dr. Jeffery investigates the potential for soy to affect bone health and for broccoli and other
crucifers with major support from NIH and USDA, and a gift from Standard Process, Inc. Dr. Jeffery is past
editor of the American Society for Pharmacology and Experimental Therapeutics Drug Metabolism Newsletter
and past associate editor of Toxicology and Applied Pharmacology. She is presently chair of the Bioactive
Components Research Interest Section of American Society for Nutritional Sciences, chair of the Toxicology
Division of American Society for Pharmacology and Experimental Therapeutics, and secretary/treasurer of the
Food Safety Specialty Section of the Society of Toxicology.
Joseph Lau, M.D. is a professor of medicine at the Tufts University School of Medicine and professor of
clinical research at the Sackler School of Graduate Biomedical Sciences at Tufts
APPENDIX F
144
University. He is also co-director of the New England Cochrane Center and director of one of the twelve Agency
for Healthcare Research and Quality Evidence-based Practice Centers located at the New England Medical
Center in Boston. Dr. Lau is interested in methodological issues in meta-analysis and the translation of evidence
into practice. He developed the method of cumulative meta-analysis and has published extensively on the
methodologies and clinical applications of meta-analysis. Dr. Lau is a member of the editorial board of Clinical
Evidence and has served on study sections for the Agency for Healthcare Research and Quality Initial Review
Group. Dr. Lau received his M.D. from Tufts University School of Medicine.
Susan S.Percival, Ph.D. is a professor in the Food Science and Human Nutrition Department at the
University of Florida. She is a recipient of the Future Leaders Award from the International Life Sciences
Institute Nutrition Foundation. Her research interests include nutrition and immunity; effects of botanicals,
phytochemicals, and trace elements on immune function; antioxidant bioavailability and impact on immunity;
efficacy of dietary supplements in humans; and mechanistic studies in animal and cell culture models. While
much of her research has focused on the metabolism of copper and other trace elements, Dr. Percival's research
currently focuses on health effects of different fruit phytochemicals, echinacea and components of green tea,
with support from industry.
Cheryl L.Rock, Ph.D., R.D. is a professor in the Department of Family and Preventive Medicine and the
Cancer Prevention and Control Program at the University of California, San Diego School of Medicine. She
received her Ph.D. in nutritional sciences from the University of California, Los Angeles School of Public
Health. Dr. Rock's primary NTH-funded research efforts are focused on the role of nutritional and dietary factors
in the development and progression of cancer in women, particularly breast and cervical cancer, and her research
efforts also address eating pathology and weight concerns in women. She is presently involved in randomized
trials that are testing whether modifications in diet and level of physical activity can alter biological processes
and progression of cancer. She currently serves on editorial boards for several peer-reviewed journals and has
been an invited participant in several NIH review committees, workshops, and meetings.

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